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  • Polymer and Materials Science  (3,047)
  • Life and Medical Sciences  (871)
  • ASTRONOMY  (473)
  • 1980-1984  (4,391)
  • 1982  (4,391)
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  • 1980-1984  (4,391)
Year
  • 101
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    Studies in astronomical time series analysis. II - Statistical aspects of spectral analysis of unevenly spaced data (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Detection of a periodic signal hidden in noise is frequently a goal in astronomical data analysis. This paper does not introduce a new detection technique, but instead studies the reliability and efficiency of detection with the most commonly used technique, the periodogram, in the case where the observation times are unevenly spaced. This choice was made because, of the methods in current use, it appears to have the simplest statistical behavior. A modification of the classical definition of the periodogram is necessary in order to retain the simple statistical behavior of the evenly spaced case. With this modification, periodogram analysis and least-squares fitting of sine waves to the data are exactly equivalent. Certain difficulties with the use of the periodogram are less important than commonly believed in the case of detection of strictly periodic signals. In addition, the standard method for mitigating these difficulties (tapering) can be used just as well if the sampling is uneven. An analysis of the statistical significance of signal detections is presented, with examples
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 263
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  • 102
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    Spectroscopy of two BL Lacertae objects (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: As part of a continuing program of observations of Bl Lac objects, the IUE cameras were used to look at PKS 0548-322 and PKS 2155-304. The spectra obtained are well described by power laws with alpha approximately 0.8 in each case. For each object, one set of simultaneous X-ray data was obtained using the solid state spectrometer (SSS) on the Einstein Observatory. These data show that the power law extends from ultraviolet frequencies into the X-ray regime, although it steepens slightly for PKS 2155-304. Both objects are variable in the ultraviolet and/or X-ray; in neither case does the small spectral variability appear to correlate with the intensity variability. The overall spectrum of these objects is interpreted in light of a synchrotron self-Compton model with relativistic beaming.
    Keywords: ASTRONOMY
    Type: Advan. in Ultraviolet Astron.; p 177-180
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  • 103
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    Time variations in C IV lambda 1550 and Ly alpha emission lines in NGC5548 (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Two short-wavelength images of NGC5548 were obtained and separated by a three month interval. Combining this data with that obtained by Wu et al. One year prior to the first image, time variations were discovered in the C IV lambda 1550 and Ly alpha profiles as well as in the intensity ratio. In the image obtained in November 1980, the C IV profile is essentially the same as that of WU et al. However, the November Ly alpha profile is substantially narrower and the Ly alpha to C IV intensity ratio is reduced by roughly a factor of 2. In our February, 1981 image, the C IV profile is narrowed by approximately a factor of 2 compared with the other two observations, while the Ly alpha profile and Ly alpha to C IV ratio is essentially the same as in November. Also a short-wavelength image of the very bright Seyfert galaxy Fairall 9 were obtained an it was found that the C IV and Ly alpha lines in this object have essentially identical profiles.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 170-176
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  • 104
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    Markarian 36: A young galaxy (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The UV, optical, and IR observations of three galaxies (NGC 4214, NGC4670 = Haro 9, and Markarian 36) are reported. The optical spectrum of Markarian 36, a dwarf galaxy, is dominated by strong emission lines. The UV spectrum however shows no strong emission lines, only weak C IV and Si absorption and a strong blue continuum that is still rising shortward of Lyman alpha. Combined UV, optical and IR observations show that the continuum is nearly Rayleigh-Jeans from 1100 A to 2.2 microns, with a slight excess in the optical due to free-free emission and recombination lines. This galaxy has few, if any, red stars. Combined with its low metal content, this lack of red stars is a very strong indication that this galaxy has only recently begun to form stars.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 151-155
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  • 105
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    The impact of IUE observations on our knowledge about galaxies and quasars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Observations of extragalactic objects with IUE are discussed. Elliptical galaxies show the presence of very hot stars which are probably highly evolved horizontal branch objects, although the observations are not adequate to rule out young OB stars. Spiral and irregular galaxies often show evidence of young OB stars although the nucleus of M31 is very similar to elliptical galaxies. Several narrow emission line galaxies appear to have nonthermal continua. Observations of Seyfert galaxies permit detailed studies of the continua and line ratios such as L alpha to H beta to be made. Unlike quasars, there is evidence for dust based on the 2175 A feature. The problem of understanding Seyfert galaxy spectra is no easier than that for quasars although observed variability in the broad lines may present useful clues. Observations of high redshift quasars with IUE allow spectra to be obtained down to rest wavelengths of a few hundred Angstroms and provide information about the amount of ionizing flux. Observations of low redshift quasars can be used to test whether the myriads of absorption lines seen below L alpha in high redshift quasars are indeed produced by intergalactic clouds and halos of intervening galaxies.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 46-53
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  • 106
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    A search for UV line variability in R136a (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The brightest object in the central cluster of stars in the 30 Doradus nebula is R136a. Optical imaging and ultraviolet spectroscopy show that a luminosity originates in a volume less than 0.1 pc across. A very tight cluster of approximately 30 luminous O and WR stars produces this energy. An alternative interpretation is the possibility that a single supermassive object dominates the light. The visual spectrum is classified as WN 4.5. A common characteristic of WN spectra is variability of the emission lines, especially He II lambda 4686.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 620-624
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  • 107
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    The Orion nebula star cluster (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Photography through filters which suppress nebular light reveal a clustering of faint red stars centered on the Trapezium, this evidences a distinct cluster within the larger OB1 association. Stars within about 20 ft of trapezium comprise the Orion Nebula star cluster are considered. Topics discussed re: (1) extinction by dust grains; (2) photometric peculiarities; (3) spectroscopic peculiarities; (4) young variables; (5) the distribution and motion of gas within the cluster.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 606-609
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  • 108
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    UV fluxes and effective temperatures of extreme helium stars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Low resolution IUE spectra of a complete ensemble of extreme helium stars are presented and their appearance in comparison with normal stars is discussed. Effective temperatures from these observations by means of line blanketed model atmospheres are determined. It is found that the temperatures are in accordance with earlier results from ground based observations.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 593-596
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  • 109
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    Ultraviolet photometry of A-type stars at high galactic latitudes (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Ultraviolet photometry on the International Ultraviolet Explorer (IUE) was used to study four stars located in one target of an earlier diffuse background sounding-rocket experiment. The resulting stellar correction is much smaller than that previously estimated, giving a higher diffuse background at this target. Visible photometry appears to be a better indicator of ultraviolet flux than spectral type. The discrepancy between previous predictions and the present observations is explained in terms of: (1) misclassification of two stars; (2) use of a spectral type/effective temperature calibration hotter than more recent determinations; and (3) inadequacy of the Kurucz models, in the far ultraviolet, for A-type stars.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 597-601
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  • 110
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    Ultraviolet spectra of some bright later type Be stars and A-F shell stars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Anomalous ionization (C IV and Si IV is seen in IUE spectra of Be stars as late as B8, and occurs also in standard stars of similar spectral type. Asymmetrical lines suggesting mass loass are present in all the Be stars and several of the standard stars as well, with no obvious correlation with v sin i. Emission shoulders are present in the Mg II lines of two B5e stars but not in Be stars of later type. No correlation is found with v sin i. The A-F shell stars show rich Fe iI absorption spectra in the ultraviolet, in one case with velocity structure.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 579-583
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  • 111
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    The X-ray binary, UW CMa (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The UW CMa is a close, eclipsing binary composed of an O7f primary with a stron wind and a less luminous O-type companion. It was found that UW CMa a variable X-ray source, whose X-ray variations are in phase with its optical light curve. Since both components of the binary system are O stars, accretion by a compact object is ruled out as a mechanism for generating X-rays. The UW CMa represents a new class of X-ray binaries, in which X-rays result from the collision of a wind from one star with the surface or wind of the other star. It is hypothesised that the impact of a wind against a star generates a shock wave about 0.25 stellar radii above the stellar surface, and material behind the shock front, heated to bout 10 million degrees, radiates the X-ray apparent X-ray variability is due to its location between the two stars, where it undergoes eclipses. The high temperature region maintains an ionization cavity in the wind, as detected with IUE. The ionization cavity is the source of depletion of absorbing ions in the wind between the two stars.
    Keywords: ASTRONOMY
    Type: Advan. in Ultraviolet Astron.; p 562-565
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  • 112
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    The hot components of hydrogen deficient binaries (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Low resolution IUE observations of the hot components of three very similar but peculiar objects: LSS 4300, Upsilon Sgr, and KS Per were compared. The possible evolutionary scenarios from observations and the extremely low hydrogen contents of the visible stars are discussed. It is suggested that the hot secondaries in hydrogen deficient binaries should also be hydrogen deficient.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 546-549
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  • 113
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    Results of the IUE program of monitoring the ultraviolet emission line fluxes of four binary systems: HR 1099, 2 Peg, AR Lac and By Dra (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A program to obtain IUE spectra and optical photometry and spectra of three RS CVn-type binaries (HR 1099, II Peg, and AR Lac) and the prototype BY Dra system is reported. The systems were monitored for at least one orbital phase, and periodic variations in emission line flux from II Peg and HR 1099, indicative of notational modulation of an active region on these stars were detected. It is found that for II Peg the active region is in phase with photometric minimum as expected, but for HR 1099 ultraviolet emission maximum occurs at the time of photometric maximum.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 554-557
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  • 114
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    The W Serpentis binaries with a few words on epsilon Aurigae (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Algol systems, U-Cephei and V356 Sagittarii, which should be included among the W Serpentis stars, characterized by strong ultraviolet emission lines are discussed. The spectra of the W-Ser stars are similar to those of the T-Tauri stars, and a similarity of physical conditions is indicated. A model of W-Serpentis, a B-star embedded in a thick disk, may be relevant to other exotic eclipsing systems, possibly even to obliquity of ecliptic Aurigae. The obliquity of ecliptic and the relationship to Aur, BM Orionis is reviewed; the system probably contains a pre main sequence star highly flattened by differential rotation.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 526-529
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  • 115
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    CI Cygni since the 1980 eclipse (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: During the 1980 eclipse of the 855 day period symbiotic binary CI Cyg, a data set showing high excitation resonance lines which were largely uneclipsed but brightening on an orbital timescale, and intercombination lines exhibiting pronounced but nontotal eclipses and which were fading on an orbital timescale were obtained. A model invoking a low density dissipating nebula surrounding the hot companion to explain the intercombination lines, and a shock between stellar winds to interpret the resonance lines, is described. Subsequent synoptic observations revealed continuing changes in the UV emission line fluxes consistent with those described above, except for the brightening of Mg II and the emergence of strong, not previously seen Mg V emission. Post-outburst and phase dependent changes must be included in any interpretation of this system as the archetypal symbiotic binary. Observations to be made during the 1982 October eclipse are summarized.
    Keywords: ASTRONOMY
    Type: Advan. in Ultraviolet Astron.; p 509-512
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  • 116
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    Analysis of non-interacting binaries with luminous cool primaries (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: High dispersion long wave redundant (LWR) spectra are analyzed for the differential velocity between hot and cool components of heretofore single lined spectroscopic binaries with late type giant or supergiant primaries. Cross correlation of a composite spectrum against early and late type standard stars yields relative velocities with an accuracy of 0.2 to 0.3 kms. When the orbit of the primay is known, the differential measurement from IUE gives the mass ratio of the system. Low dispersion short wave prime (SWP) and LWR flux spectra are used together with ground-based photometry to disentangle the composite energy distributions of the binaries. Temperatures of both components, their relative luminosities, and the reddening of the system are obtained. Assuming the hot secondaries to be main sequence stars, their probable luminosities and masses may be obtained from their temperatures. Then absolute magnitudes and masses may be obtained for the evolved primaries with more confidence than with existing techniques.
    Keywords: ASTRONOMY
    Type: Advan. in Ultraviolet Astron.; p 501-504
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  • 117
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    A model for the 1979 outburst of the recurrent nova U Scorpii (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A series of ultraviolet spectra were obtained of the recurrent nova U Sco during its recent outburst with the IUE satellite. These spectra were analyzed and found to consist primarily of emission lines although broad resonance absorption is present during the first week. These data, in combination with the optical data, show that the nova ejecta is very depleted in hydrogen relative to helium and is rich in nitrogen. An optical spectrum, obtained nine months after the outburst, shows predominantly He II emission lines, indicating that the gas being transferred from the secondary is very helium rich and that the secondary is highly evolved. These data are interpreted to imply that the outburst is associated with the accretion of helium rich material by a massive white dwarf in a close binary system. Neither the observational data nor the theoretical calculations, permit differentiation between a thermonuclear runway or an accretion event as the cause of the outburst. In both cases, an equal amount of material is ejected at equal speeds.
    Keywords: ASTRONOMY
    Type: Advan. in Ultraviolet Astron.; p 470-473
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  • 118
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    Data obtained from spacecraft (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Data from spacecraft observations of B stars in the ultraviolet and X-ray spectral regions are presented. Superionization, mass flux, and the extended envelope are discussed in reference to ultraviolet line spectral. The problem of determining the ultraviolet flux of the B stars is examined. Spectral variations of gamma Cas and 59 Cyg are also discussed.
    Keywords: ASTRONOMY
    Type: B Stars With and Without Emission Lines, Parts 1 and 2; p 375-407
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  • 119
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    UV emission from he M1 supergiant TV Gem (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Low and high dispersion ultraviolet spectra were obtained of the M1 supergiant TV Gem with IUE. Previous IUE observations of this late type supergiant revealed unexpected UV continuum emission, perhaps arising from an early B companion. Low resolution spectra obtained approximately one year apart suggest that the strong Si III in combination perhaps with O I at wavelengths approximately 1300 A varies considerably with time. Large variation in the column density is required to explain these changes. Sporadic mass expulsion with mass loss rates dM/dt approximately 0.00001 solar mass yr minus 1st power from the M supergiant could lead to a dense circumstellar wind near the hot early companion, and thus could account for these observed variations in equivalent width. The high resolution spectrum in the 2000 to 3200 A wavelength range is characterized by narrow absorption lines primarily due to Fe II, Mn II and Mg II (h and k), which are skewed in profile with an extended red wing. This profile structure is tentatively attributed to interstellar absorption and an intervening differentially moving cloud in the direction of Gem OB1, of which TV Gem is a known association member.
    Keywords: ASTRONOMY
    Type: Advan. in Ultraviolet Astron.; p 263-267
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  • 120
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    Chromospheric, transition layer and X-ray emission for stars with different rotational velocities (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: In agreement with previous findings for the MgII k line emission in F stars an increase of Lya and transition layer emission with increasing V sub r sin i, if v sub r sin i greater than 30 km/sec. was not found. For V sub r sin i 30 km/sec., the measured line intensities are consistent with an increase in emission with increasing V sub r sin i. Such a relation between emission and rotation for single stars is also in agreement with X-ray observations. For the young F stars in the Hyades we find generally enhanced emission independently of rotational velocities. The enhancement is most pronounced for low excitation lines.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 247-250
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  • 121
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    Chromospheric, transition layer and coronal emission of metal deficient stars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: It is shown that while MgII k line emission decreases for metal deficient stars, the Ly alpha emission increases. The sum of chromospheric hydrogen and metallic emission appears to be independent of metal abundances. The total chromospheric energy loss is estimated to be 0.0004 F sub bol. The chromospheric energy input does not seem to decrease for increasing age. The transition layer emission is reduced for metal deficient stars, but it is not known whether the reduction is larger than can be explained by curve of growth effects only. Coronal X-ray emission was measured for 4 metal deficient stars. Within a 12 limit it could still be consistent with the emission of solar abundance stars.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 231-234
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  • 122
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    The ultraviolet spectrum of the high redshift BL lac object 0215+015 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The highly variable object 0215+015 is studied. It has a range in the optical band of more than 4 magnitudes, and exhibits radidly variable polarization. At optical wavelengths it shows no emission lines but has a rich absorption spectrum with at least six, separate redshift systems. Combined are 3 LWP low-dispersion images of the object to produce a high signal-to-noise spectrum between 2400 - 3200 A which is use to study the hydrogen Lyman lines of the various redshift systems.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 193-196
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  • 123
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    Coordinated observations of Seyfert I galaxies (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A program to obtain simultaneous observations from the X-ray to the IR of Seyfert I galaxies is outlines. Of particular interest is the variability of these Seyfert nuclei. The continuum flux distribution in the UV for AkN 120 and ESO 113-IG45 (F-9) is examined.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 165-168
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  • 124
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    IUE and Einstein observations of NGC5204 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The use of both the Einstein and IUE observations of NGC5204 to test some of the hypotheses put forward as a result of an X-ray survey of blue peculiar late type galaxies is discussed. In particular the hypothesis that binary X-ray sources of Pop I progenitors are responsible for most of the X-ray emission, is strengthened by the IUE short wavelength spectrum of NGC5204. This spectrum suggests a number of OB stars in agreement with the inferred from the X-ray luminosity. It also shows an ultraviolet excess in agreement with the large X-ray to blue flux ratio.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 145-150
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  • 125
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    The distribution of interstellar gas within 50pc of the Sun (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previous Copernicus determinations of H I column densities in nearby stars are reviewed. These results are compared with recent ultraviolet (IUE) data and data acquired at other wavelengths. From this combined data set a coherent picture for the distribution of neutral hydrogen within 50pc of the Sun emerges. For directions away from the galactic center, the total H I column density for a 50pc line of sight is typically approximately 10 to the 18th power/sq cm, while toward the galactic center it may be 1 to 2 x 10 to the 19th power/sq cm or higher. A tentative model is proposed which suggests that the bulk of the H I resides in a cloud in a direction toward L(II) approximately 0 deg. The data are consistent with the Sun being embedded, but near the edge of the cloud.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 125-133
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  • 126
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    IUE spectroscopic investigation of interacting binary systems (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The IUE observations of binaries consisting of at least one early type star, to the Algol systems, and to W Serpentis systems are discussed. The OB close binaries almost invaribly show a stellar wind. The difference between an unevolved early type system and a slightly evolved system is difficult to discern observationally and probably not meaningful in terms of Roche lobes. the zeta Aur stars show complex gas motions and shocks. Many of the Algol systems show peculiarities in their ultraviolet continua and the resonance lines, particularly Si IV, are of abnormal and variable strength. Emission lines were detected in several systems during the total eclipse. The W Ser stars are characterized by numerous strong emission lines in their ultraviolet spectra. It appears that these systems may be related to beta Lyrae as they seem to be in a phase of rapid mass transfer and their spectra show similarities to that of beta Lyrae.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 102-113
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  • 127
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    Abundance fluctuations in the interstellar medium (1982)
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    Publication Date: 2011-08-18
    Description: The determination of abundances within the interstellar medium is reviewed. It appears that interstellar abundances within 1 kpc of the Sun are uniform to within a factor of two or three, but it is not yet possible to determine whether there are real fluctuations at this level except for deuterium for which the factor of two variations appear to be real. Establishing the level of local fluctuations in the abundances is of considerable importance for understanding the history of nucleosynthesis in the solar neighborhood, the evolution of the interstellar medium and the formation of stars.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 54-60
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  • 128
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    Mass loss from cool stars, facts, fads, and fallacies (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The accumulation of observational material (ultraviolet spectroscopic measures, quantitative optical spectroscopy, and X-ray photometry) and its use in discerning the presence and character of mass loss across the cool half of the H-R diagram and establishing constraints on theoretical models are discussed. Analogies with closed and open solar magnetic structures are found. Two determinants of atmospheric wind structure, temperature and gravity, may suffice in a most superficial way to define the wind and atmospheric structure in a star, however it is apparent that there is still a missing parameter which may stem from magnetic activity and its particular configuration. Theories that appear successful in reproducing observed line profiles, wind temperatures, and terminal velocities incorporate Alfven wave heating and momentum deposition. Successive observations of an active binary (lambda and G8III-IV) and a supergiant star, alpha Aqr (G2 Ib) revealed that magnetic activity and perhaps mass loss occur on restricted regions of a stellar surface and that long-term structures are present in the wind. These phenomena are present in the solar atmosphere and wind and may be considered a general characteristic of stellar winds.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 3-16
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    Radio astronomy (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Use of the Tidbinbilla Interferometer to refine the source positions in the Parkes 2.7 GHz survey of the southern sky is described. A result of the first phase of this work was the identification of a quasi-stellar object which appears to be the most remote object yet observed. This object has a red shift of 3.78 (PKS 2000-330, and a velocity of recession equal to 91% of that light. Based on Hubble's law, PKS 2000-330 appears to be 12 billion light years away.
    Keywords: ASTRONOMY
    Type: The Telecommun. and Data Acquisition Rept.; p 1-2
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  • 130
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    Ultraviolet observations of nova Aquila, 1982 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A bright nova in Aquila was discovered with a visual magnitude of 6 to 7. A number LWR and SWP spectra of the object were obtained with the IUE. The nova has a heavily reddened spectrum, E(B-V)= 0.55 + or - 0.15, and a complex shot wavelength spectrum with both narrow emission features and broad absorption troughs, indicating terminal velocities as high as 10,000 km/s. Both the continuum flux and the absorption line profiles changed between two observations. Short period variations were also observed.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 625-628
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  • 131
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    The nova-like variable KQ Mon and the nature of the UX Ursa Majoris stars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The KQ Mon is a UX UMa type nova-like variable discovered by Howard Bond. Optical spectra taken by Bond in 1978 reveal very shallow Balmer absorption lines and He I absorption. Bond also did UBV and high speed photometry in 1978 and early 1981. There has been no evidence of orbital variations but the appearance of the optical spectrum and the presence of low amplitude flickering suggested a strong similarity to CD-42-14462 (=V3885 Sgr) and other members of the UX UMa class. Low dispersion observations of KQ Mon were made with the International Ultraviolet Explorer satellite. Six spectra taken with the shot wavelength prime camera are dominated by strong broad absorption lines due to N V, O I, Si III, Si IV, C IV, He II, N IV, and Al III. There is little evidence of orbital phase modulation over the time baseline of the observations. Unlike UV observations of other UX UMa type objects, KQ Mon exhibits no emission lines or P Cygni type profiles and the velocity displacements appear to be smaller, suggesting the absence of a hot, high velocity wind characterizing other UX UMa stars. The relationship of KQ Mon to other UX UMa disk stars is discussed and a model is suggested to explain their observed properties and the lack of major outbursts.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 460-464
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  • 132
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    Low resolution ultraviolet and optical spectrophotometry of symbiotic stars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Low resolution International Ultraviolet Explorer spectra combined with optical spectrophotometry provide absolute flux distributions for seven symbiotic variables from 1200 to 6450 A. For five stars (EG And, BF Cyg, CI Cyg, AG Peg, and Z And) the data are representative of the quiescent/out-of-eclipse energy distributions; for CH Cyg and AX Per, the observations were obtained following their atest outburst in 1977 and 1978, respectively. The de-reddened distributions reveal a remarkable diversity of both line spectra and continua. While the optical and near infrared regions lambda = 5500 A) are well represented by single component stellar models, multicomponent flux distributions are required to reproduce the ultraviolet continua.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 448-451
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  • 133
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    Hydrogen two photon emission in the UV spectrum of type 2 supernovae (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The continuum emission of Type 2 supernovae demonstrates an ultraviolet (UV) excess when fit by black body emission is attempted. The H two photon emission is advanced as an explanation of the UV excess. A function by which the UV spectra of two Type 2 supernovae (SN 1979c in NGC 4321 and SN 1980k in NGC 6946) are fitted with U,B,V photometric data is presented. The angular velocity of expansion of the supernovae envelope is derived. From this, the linear velocity of expansion and the distances of the parent galaxies are derived. A distance of 17.3 Mpc is obtained for NGC 4321, and a distance of 7.1 Mpc for NGC 6946.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center Advan. in Ultraviolet Astron.; p 434-437
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  • 134
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    Astronomy on ice (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A solar seismology program based on observations made at the South Pole is discussed. Environmental and observing conditions at the South Pole are reviewed, and the solar telescopes used in the program are described. The history of solar seismology and of observations of solar surface oscillations is briefly summarized. It is noted that the South Pole was chosen as the site for the program to obtain good frequency resolution and that the observations have produced more than 600 million bytes of computer data.
    Keywords: ASTRONOMY
    Type: Sky and Telescope; 64; Dec. 198
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  • 135
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    On the detection of other planetary systems by astrometric techniques (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A quantitative method for astrometrically detecting perturbations induced in a star's motion by the presence of a planetary object is described. A periodogram is defined, wherein signals observed from a star show exactly periodic variations, which can be extracted from observational data using purely statistical methods. A detection threshold is defined for the frequency of occurrence of some detectable signal, e.g., the Nyquist frequency. Possible effects of a stellar orbital eccentricity and multiple companions are discussed, noting that assumption of a circular orbit assures the spectral purity of the signal described. The periodogram technique was applied to 12 yr of astrometric data from the U.S. Naval Observatory for three stars with low mass stellar companions. Periodic perturbations were confirmed. A comparison of the accuracy of different astrometric systems shows that the detection accuracy of a system is determined by the measurement accuracy and the number of observations, although the detection efficiency can be maximized by minimizing the number of data points for the case when observational errors are proportional to the square root of the number of data points. It is suggested that a space-based astrometric telescope is best suited to take advantage of the method.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 263
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  • 136
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    Observations of the red auroral oxygen lines in nine comets (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The digital sky-subtracted spectra of nine cometary nuclei are used to measure the 6300, 6363-A Auroral red doublet of the O I forbidden line, and in view of the confinement of the cometary oxygen lines to their nuclear source, a small but variable correction for NH2 blending in different comets is made. For seven of the comets measured, and under the assumption of H2O's exclusive role as the oxygen parent, the average Q(H2O)/Q(O I) ratio is about 20. This is in excellent accord with theory, and it is conjectured that the O I production rate can be used to scale the total cometary volatile loss in even faint, distant comets. The data obtained are consistent with heliocentric production rates that vary as power laws, with n values of 2.0 for 'gassy' comets and nearer to 5.0 for dusty ones. The comets with the greatest volatile mass-loss rates all were found to have dusty spectra.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 94
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  • 137
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    Conversion of positions and proper motions from B1950.0 to the IAU system at J2000.0 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The complete transformation of positions and proper motions from B1950.0 to J2000.0 on the basis of IAU recommendations including the transition from FK4 to FK5 equinox may be rigorously accomplished with a simple vector equation. The equation is first presented in this paper and then subsequently derived. The transformation of the FK4 to FK5 system described by functions f(alpha, delta, m) is in preparation in Heidelberg.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics; 115; 1, No; Nov. 198
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  • 138
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    Orientation of the JPL Ephemerides, DE 200/LE 200, to the dynamical equinox of J 2000 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The lunar and planetary ephemerides, DE 200/LE 200 have been recently produced at JPL. They will form the basis of the ephemerides in the 'Astronomical Almanac' starting in the year 1984. The origin has been referenced to the J 2000 dynamical equinox of the ephemerides themselves. The procedure for this orientation is described here in detail. Analyses of the ephemerides also provide comparisons with the equinox of the FK 4 and with presently adopted values for the earth's obliquity.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics; 114; 2, Oc; Oct. 198
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  • 139
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    Facilities for US radioastronomy (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An overview of the radio-astronomy field is given, and prospects ready for construction at NASA are presented. A very-long-baseline array consisting of ten 25 m antennas, with a limiting wavelength of 7 mm and an angular resolution at that wavelength of 2 x 10 to the 4th arcsec is discussed. Eighty percent of the phase information will be obtained by closure around the 36 independent triangles, and high quality aperture-synthesis maps will be produced at all wavelengths. The 25 m telescope will be capable of several applications including the discovery of new molecules in our galaxy (in particular, the envelope of the evolved carbon star IRC + 10216), the detection of CO to distances of perhaps 100 million light years, and the understanding of the events which occur as stars are formed from molecular clouds, and as energy is fed back into the molecular gas by new stars. The submillimeter-wave telescope contains the last atmospheric radio windows where astronomical observations can be made from the earth's surface. The need for funding is stressed.
    Keywords: ASTRONOMY
    Type: Physics Today; 35; Nov. 198
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  • 140
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    Spectra of cosmic X-ray sources (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-25087)
    Keywords: ASTRONOMY
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  • 141
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    Cometary ephemerides for spacecraft flyby missions (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The determination of cometary ephemerides is considered with reference to proposed missions to Comet Halley. It is noted that the ability of spacecraft without onboard navigation capability to fly close to target comets is limited chiefly by the comet's ephemeris uncertainty. The situation is complicated by nongravitational forces acting on a comet's nucleus and the paucity of observers currently making astrometric observations of comets. The nongravitational forces affecting Comet Halley are consistent with the rocket effect of an outgassing water ice nucleus; the nucleus is apparently rotating in a direct sense about a stable spin axis. It is emphasized that accurate Comet Halley ephemerides for close spacecraft flybys will require continued efforts to refine the existing nongravitational force model. In addition, the flyby mission to Comet Halley will require a well-organized network of astrometric observers. For this purpose, an Astrometry Network is being set up within NASA's International Halley Watch program.
    Keywords: ASTRONOMY
    Type: (ISSN 0273-1177)
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  • 142
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    A search for spectroscopic binaries among the runaway O type stars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Numerous radial velocity measurements of medium dispersion were made for the 10 brighter stars given in Stone's list of very probable O type runaways. All plates were measured with the KPNO PDS microdensitometer, and a new iterative reductional analysis was used to derive plate velocities, which are estimated to be 1.6 times more accurate internally than those found by using the traditional method. Of thse stars, psi Per, alpha Cam, HD 188209, and 26 Cep are identified as probable velocity variables, while 9 Sge, lambda Cep, and HD 218915 are classed as possible variables. If the source of this variability is Keplerian rather than atmospheric, which cannot be established unequivocally from the observations of this paper, psi Per could be a spectroscopic binary with a black hole companion, and at least 1.2 solar mass. The detection of runaway binary systems from radial velocity measurements is discussed.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 261
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  • 143
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    Middle-ultraviolet photometry of Virgo cluster galaxies (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Photographic photometry of Virgo cluster galaxies has been performed in a wavelength band extending from 1620-3200 A using sounding rocket techniques. The observational results are middle ultraviolet magnitudes, U2421, or faint limits for U2421, for 201 galaxies within 5.5 arcmin of the cluster center. A strong negative correlation is found between U2421 - V and V for all observed S0 galaxies and a similar but weaker correlation for the observed ellipticals. No such correlation is found for spiral galaxies regardless of their projection angles on the sky. The measured colors are generally compatible with colors computed from previously generated composite spectra.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 261
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  • 144
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    On the linearity of the SWP camera of the international ultraviolet explorer /IUE/ - A correction algorithm (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An algorithm is presented for correcting IUE low resolution spectral images obtained with the SWP camera for some of the non-linearity effects reported by Bohlin et al. (1980). The non-linearity problem, which affects SWP images processed at Goddard Space Flight Center in the period May 22, 1978 to July 7, 1979 and at VILSPA in the period June 14, 1978 to August 6, 1979, was essentially due to the use of an Intensity Transfer Function (ITF) that erroneously included a blank image in the 20 percent exposure level. The correction algorithm described here was adopted by the three IUE Agencies in November 1979 as being suitable for most IUE users. It has the advantages to be applicable to any kind of low resolution SWP spectra, to introduce errors which are usually less than the intrinsic photometric errors, and to be of simple application. The results obtained by applying the method to a representative set of spectra of both point and extended sources are reported. In addition, a new evaluation of linearity and reproducibility of the SWP spectral data is provided, based on the improved ITF.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics; 112; 2, Au; Aug. 198
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  • 145
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    A brightening of the symbiotic variable SY Muscae (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The symbiotic variable SY Muscae has been observed with IUE in September 1980 and June 1981 and in the photographic region in May 1981. The entire ultraviolet spectrum brightened between September and June by about a factor of 5. The spectrum shows high excitation including emission from N v and high electron density, about 10-billion per cu cm as determined from various line ratios in the ultraviolet. The optical spectrum is dominated by permitted lines; even forbidden O III is very weak again indicating high density in the ionized region. The increase in ultraviolet continuum and line emission may be due to enhanced mass transfer from the cool star whose period is 623d and whose maximum was predicted to occur very close to the time of the June 1981 observations. Alternatively the hot star and much of the emitting gas could have been in eclipse in September 1980.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics; 109; 1, Ma; May 1982
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  • 146
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    Near-infrared spectrophotometry of four Seyfert 1 galaxies and NGC 1275 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Low-resolution spectrophotometry from 2 to 4 microns is reported for the four Seyfert 1 galaxies Mrk 335, 3C 120, Mrk 509, NGC 7469, and the peculiar emission-line galaxy NGC 1275. The spectrum of NGC 7469 exhibits a strong 3.3-micron dust feature, indicating a thermal origin for the bulk of its considerable nonstellar infrared emission. NGC 1275 has a large stellar contribution to its infrared flux at wavelengths shortward of 3 microns. The spectrum from 3 to 4 microns fits a power law which fits the 10-micron and 20-micron broad bands, as well. A thermal model which can explain the spectrum of NGC 1275 is discussed. Mrk 335 displays a complex spectrum suggestive of thermal dust emission. 3C 120 and Mrk 509 have nonstellar infrared emission shortward of 2 microns, but the data are ambiguous as to whether this emission is thermal or nonthermal in origin.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 257
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  • 147
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    Near-infrared photometry of distant radio galaxies - Spectral flux distributions and redshift estimates (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Calculations modeling the effects of stellar evolution on the observed colors of elliptical galaxies suggest that the shape of their spectra should remain almost constant in the red and near-infrared for red shifts greater than two. In order to test this idea, JHK photometry of optically faint radio source identifications believed to be faint elliptical galaxies were carried out. Photometric redshift estimates have been made using three different models: a nonevolving elliptical galaxy spectrum, an evolving spectrum based on one of Bruzual's calculations, and an empirical model derived from photometry of distant elliptical galaxies. Redshifts greater than 0.5 are systematically under-estimated by the first two models and for galaxies whose colors are not consistent with the models, deviations occur not only in the optical bands but also in the infrared. The difficulties are not resolved by the addition of a quasar-like nucleus to the galaxies.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 257
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  • 148
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    On the distribution of orbits among long-period comets (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The distribution of the axes defining the planes and orientations of the orbits of 542 long-period comets are analyzed. The directions of the perihelia and of the oriented plane normals show significant nonuniformity in their distributions. The preferred direction of perihelia near the apex of solar motion is refined to an (1 sigma) error circle of 20.6 deg, and possible concentrations of the plane normals and the directions of perihelion velocity along roughly orthogonal directions are noted, although the error circles extend to nearly full hemispheres. Planes of preference (and avoidance) are found from the distribution ellipsoids of the three orbital axes, with the perihelion directions lying preferentially along the galactic plane. The distribution ellipsoids of all three sets of orbital axes exhibit anisotropies roughly twice those expected for random distributions.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 87; June 198
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  • 149
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    Detection of pedestal features in dark clouds - Evidence for formation of low mass stars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: To assess whether B335 is unique among dark clouds or whether CO-12 pedestal features are quite common, 180 opacity class 5 and 6 Lynds clouds were surveyed. From this set of data, three additional sources were found to have pedestal features. These suggest the presence of embedded low-mass stars, though a hot differentially rotating disk cannot be excluded for B335. Estimates of the mass-loss rate required to produce stellar winds consistent with observations are comparable with mass-loss rates for T Tauri stars. Further, the pedestal feature formation rate is similar to the local low-mass star formation rate.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 256
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  • 150
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    E/B - V/ extinction values for 24 planetary nebulae derived from IUE data (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Excellent agreement was found for E(B - V) values for nine planetary nebulae observed in common by IUE and ANS, derived from a strong 2200A absorption feature. E(B - V) values for seven additional objects with moderately strong 2200A absorption were determined. A third group of eight planetary nebulae for which the 2200A absorption feature is marginal or absent had E(B - V) extinctions determined from the observed He II I(1640A)/I(4686A) ratio. A comparison with optical and radio data is included.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 87; Mar. 198
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  • 151
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    IUE data reduction - The parameterization of the motion of the IUE reseau grids and spectral formats as a function of time and temperature (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Improvements are made on IUE data reduction using corrected reseau positions and dispersion constants for temperature variations and secular effects. Models describing the motion of the high dispersion spectral format as a function of THDA alone reduce the scatter in the predicted position of a given wavelength, and scatter is further reduced when a linear dependence on time is also allowed. A correction technique is presented for early data which reduces errors in wavelength assignments from over 30 km/s to less than 3 km/s in high dispersion. The reseau temperature correction helps locate the minimum background signal, centered between the echelle orders. The residual uncertainty of 2 km/s for SWP and 2.7 km/s for LWR makes the wavelength accuracy of time and temperature corrected IUE spectra comparable to that of temperature corrected data from the Copernicus satellite.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics; 107; 1, Ma; Mar. 198
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  • 152
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    Ultraviolet observations of four symbiotic stars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Observations were obtained with the International Ultraviolet Explorer (IUE) of four symbiotic stars. The UV spectra of YY Her, SY Mus, CL Sco, and BX Mon are characterized by varying degrees of thermal excitation. These low resolution spectra have been analyzed in terms of line-blanketed model atmospheres of early A, B, and F type stars in order to identify the nature of the hot companion in these systems. The expected emission from early main sequence stars does not fully explain the observed distribution of UV continuum energy over the entire IUE spectral range (1200-3200 A). More likely the observed continuum may be originating from an accretion disk and/or hot subdwarf that photoionizes circumstellar material, and gives rise to the high excitation lines that have been detected. The Bowen fluorescent excited lines of O III in SY Mus exhibit slightly broadened profiles that suggest possible turbulent motions in an extended circumstellar cloud with characteristic velocities of approximately 300 km/s.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 253
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  • 153
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    A complete X-ray sample of the high-latitude /absolute value of b greater than 20 deg/ sky from HEAO 1 A-2 - Log N-log S and luminosity functions (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An all-sky survey of X-ray sources was performed, complete to a limiting sensitivity of 3.1 x 10 to the -11 ergs/sq cm/s in the 2-10 keV band. The complete sample has allowed construction of luminosity functions based on a flux-limited sample for clusters of galaxies and active galactic nuclei. Integration of the best-fit luminosity functions indicates that clusters of galaxies contribute about 4% of the 2-10 keV DXRB, and active galactic nuclei about 20%. It is predicted that many of the objects seen in the deep survey should be local, relatively low luminosity active galactic nuclei and clusters of galaxies.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 253
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  • 154
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    Observations of NGC 604 over six decades in frequency (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Maps in the near-infrared, H-alpha and radio continuum have been obtained of NGC 604, the brightest H II region complex in M33, as well as a measurement of the UV spectrum of the ionizing star cluster. The data show that NGC 604 consists of about ten components of typical size 10 pc, embedded in a much larger envelope with dimensions of 225 pc. At least one component is optically almost completely obscured; it is located close to another object that is only detected in the near-infrared and whose nature is uncertain.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics; 105; 2, Ja; Jan. 198
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  • 155
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    The excitation and distribution of CO (J = 6-5) emission in the Orion Nebula (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Observations of the 691-GHz (J = 6-5) transition of CO in the BN/KL region of Orion obtained in February 1981, at the IR Telescope Facility at Mauna Kea are reported. The system employs a heterodyne receiver with an overall noise temperature of 3900 K DSB at 432 microns, 64 5-MHz IF-filter-bank channels, and a chopping secondary with 120-arcsec excursion, and has 35-arcsec resolution. Sample data are presented graphically and analyzed using a rate equation and a kinetic model. A 35 x 45-arcsec core with hot broad plateau emission (antenna temperature 180 + or - 36 K) surrounded by an area of strong narrow-line 120-K emission is found. It is suggested that the plateau emission originates in a wide thin sheet after a shock wave, with H2 density at least 10 to the 6th/cu cm and gas kinetic temperature greater than 500 K.
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  • 156
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    Astrometric observations and the motion of comet Halley (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Beginning with studies related to the 1835 appearance of comet Halley, it became apparent that comets may undergo substantial nongravitational perturbations due to the rocket-like effect of an outgassing cometary nucleus. Marsden (1968, 1969) modeled these nongravitational effects with a semiempirical term in the cometary equations of motion. The most successful orbital solution was consistent with an outgassing water ice nucleus in direct rotation. For the conduction and coordination of accurate astrometric observations of comet Halley, an Astrometry Network is being established within the International Halley Watch program. Attention is given to the support of the Halley flight projects provided by the Astrometry Network, and the support of ground based observers by this network.
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  • 157
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    The International Halley Watch (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The International Halley Watch (IHW) is a program designed to promote cooperation, standardization, and archival documentation in all phases of study of Comet Halley during its 1985-86 apparition. Discipline Specialists have been selected to create cooperative nets of ground-based observers encompassing seven different technical areas and to coordinate the observations and publication of results in each. The IHW will promote cooperation among ground-based and space studies of Comet Halley wherever reasonable and feasible. More specifically, the IHW will make ephemerides from the astrometric net available to any country flying a deep space mission. It will coordinate special Halley Watch Days with the arrival dates of space probes or periods of observation from earth orbit. And the IHW will provide a permanent archive in published form of all scientific observations of Comet Halley.
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  • 158
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    A worldwide photographic network for wide-field observations of Halley's Comet in 1985-1986 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A global network of ground-based observatories for the study of Halley's Comet in 1985/1986 is discussed. Recommendations are made with respect to improving coordination between reporting observatories, in order to ensure detailed imaging of such fast-generating cometary phenomena as plasma-tail knots, helices, disconnected tails, rays and condensations. A method for calibrating telescopes is considered by which well-studied objects will be photographed to provide references for images of Halley's Comet. This procedure is expected to reduce errors to approximately 0.05 mag. A coordinated study of Halley's Comet will provide important data on the physical properties of the Comet. Examples of the topics of study related to the plasma physics of the Comet's tail include: magnetic reconnection, rippling and tearing modes, kink instability, Kelvin-Helmholtz instability, and the flute instability.
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  • 159
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    Hydrodynamic stability of jets produced by mass accreting systems (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The existing model for pulsed X-ray emission from the source Hercules X-1 is reviewed. A necessary part of this model is a processing accretion disk which turns the source on and off with 35 day cycle. It is usually assumed that precession of the primary star in this binary system, Hz Hercules, slaves the disk to its precession rate. This model can account for the system behavior in a qualitative manner. Precession of Hz Hercules with 35 day period requires precession of the binary orbit. Pulse arrival times from Herc X-1 have been analyzed for orbital precession. The inclusion of precession does not significantly improve the results obtained assuming a non-precessing orbit. The fluid dynamical stability of extra-galactic jets and the possible consequences of Kelvin-Helmholtz instability at the jet surface external medium interface are considered.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center The 1982 NASA(ASEE Summer Fac. Fellowship Program; 12 p
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  • 160
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    X-ray astronomy program in Japan (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Hakucho satellite operations and the problems that emerged from the neutron star observations are illustrated. X-ray pulsars and bursters are reviewed. Future satellite programs are outlined.
    Keywords: ASTRONOMY
    Type: NASA. Goddard Space Flight Center X-ray Astronomy in the 1980's; p 219-226
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  • 161
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    Infrared observations of low-mass star formation in Orion - HH objects (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The results of a preliminary analysis of IR data on Herbig-Haro objects in the Orion nebula are reported. The observations were made with the high angular resolution IR photometry equipment on the NASA Kuiper Airborne Observatory and the NASA facility on Mauna Kea, HI. Data were taken in the 1-200 microns region with 40, 6, and 8 arcsec resolution. Attention was focused on NGC 1999 (HH1-3) and M78 (HH24-25) and the determination of absolute luminosities of the exciting stars. Measurements were also made of the IR energy distribution in the thermally emitting dust clouds and the point sources. Herbig-Haro objects featured compact and far IR sizes and large visual extinction, in addition to a steeply rising energy distribution up to 50-100 microns, where the luminosity emitted was concentrated.
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  • 162
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    Observations of RR Lyrae with the ANS satellite (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Photometric observations of RR Lyr in the ultraviolet have been obtained using the Astronomical Netherlands Satellite. The observations are compared with theoretical light curves calculated using synthetic spectra and angular diameters determined as a function of phase for RR Lyr by Manduca et al. from photometry at longer wavelengths. A good agreement is found. A bump in the observed light curves in the phase range 0.6 to 0.8 supports the existence of a shock as predicted by Hutchinson, Hill, and Lillie.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 94
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  • 163
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    The Pinhole/Occulter Facility (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The Pinhole/Occulter Facility concept uses a remote occulting mask to provide high resolution observations of the solar corona and of astronomical X-ray sources. With coded-aperture and Fourier-transform techniques, the Pinhole/Occulter makes images at a resolution of 0.2 arc sec for 2-120 keV X-rays, using a 50-m boom erected from the payload bay of the Space Shuttle or mounted on a free-flying platform. The remote occulter also creates a large shadow area for solar coronal observations; the Pinhole/Occulter concept includes separate optical and ultraviolet telescopes with 50-cm apertures. These large telescopes will provide a new order of resolution and sensitivity for diagnostic observations of faint structures in the solar corona. The Pinhole/Occulter is a powerful and versatile tool for general-purpose X-ray astronomy, with excellent performance in a broad spectral band complementary to that accessible with AXAF. The large collecting area of 1.5 sq m results in a 5 sigma detection threshold of about 0.02 microJy for the 2-10 keV band.
    Keywords: ASTRONOMY
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  • 164
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    New members of the infrared cluster in the Orion Molecular Cloud (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Near-infrared high-resolution scans (3.5 arcsec) of the core of the Orion Molecular Cloud (no. 1) have revealed 26 sources. Eleven of these are identified with faint visible stars. The remainder are thought to be highly reddened stars embedded in the molecular cloud and include at least two of the previously known infrared cluster members. Comparison of the distribution of infrared and visible stars on the plane of the sky and in an infrared color-magnitude diagram shows that the obscured infrared sources form a separate cluster of stars. The newly discovered sources appear to fall into two categories: (1) optically identified stars probably on the front surface of the cloud and associated with the Trapezium cluster; and (2) unidentified infrared stars probably associated with the molecular cloud and the embedded infrared cluster. It is plausible that the newly discovered infrared sources in the OMC-1 region are stars less massive than the previously known members and younger than visible stars of similar mass in Orion Association.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 87; Dec. 198
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  • 165
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    Medusa spectroscopy of A400, A576, A1767, and A2124 (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Galaxy velocity data taken with the Steward Observatory multiple aperture fiber optic spectrograph are presented for four Abell clusters. The root-mean-square external errors in these velocities are about 100 km/s; accuracy which compares favorably with that obtained from single-object observations. It is expected that the recent adoption of a CCD detector should decrease external errors to about 50 km/s. All four of the clusters observed are known X-ray sources and the present data agree well with empirically derived velocity dispersion-X-ray luminosity relations for clusters of galaxies. Abell 400 is interesting in this regard, since both its X-ray luminosity and its velocity dispersion are quite small. Such objects are particularly important in determining the slope of the velocity dispersion-X-ray luminosity relation. The large microwave decrement observed in A576 was initially interpreted as due to Compton scattering of the microwave background by the X-ray-emitting intracluster gas. White and Silk have presented Einstein X-ray data which indicate that A576 contains too little gas to produce the observed microwave decrement by Compton scattering. The velocity dispersion obtained here for 47 members of this cluster strengthens their conclusion.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 87; Dec. 198
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  • 166
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    A mercuric detector system for X-ray astronomy. 2. Results from flight tests of a balloon borne instrument (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: To establish the expected sensitivity of a new hard X-ray telescope design, an experiment was conducted to measure the background counting rate at balloon altitudes (40 km) of mercuric iodide, a room temperature solid state X-ray detector. The prototype detector consisted of two thin mercuric iodide (HgI2) detectors surrounded by a large bismuth germanate (Bi4Ge3O12) scintillator operated in anticoincidence. The bismuth germanate shield vetoed most of the background counting rate induced by atmospheric gamma-rays, neutrons and cosmic rays. A balloon-borne gondola containing a prototype detector assembly was designed, constructed and flown twice in the spring of 1982 from Palestine, Texas. The second flight of this instrument established a differential background counting rate of 4.2 O.7 x 10-5 counts/sec cm keV over the energy range of 40 to 80 keV. This measurement was within 50% of the predicted value. The measured rate is approx 5 times lower than previously achieved in shielded NaI/CsI or Ge systems operating in the same energy range. The prediction was based on a Monte Carlo simulation of the detector assembly in the radiation environment at float altitude.
    Keywords: ASTRONOMY
    Type: NASA-CR-175329 , NAS 1.26:175329
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  • 167
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    AXAF, a permanent orbiting X-ray observatory - Telescope and instrumentation plans (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The Advanced X-ray Astrophysics Facility (AXAF) now under study is to be a long-lived X-ray observatory in space. It is to be launched by the Space Shuttle, maintainable on-orbit, and retrievable for ground re-furbishment. The AXAF is conceived as an X-ray telescope with 6 nested grazing incidence X-ray mirrors (with a maximum aperture of 1.2 microns) and interchangeable and repleceable focal plane instruments. The optics will provide 0.5 arcsecond imagery over a several arcminute field and somewhat reduced resolution over 1 degree in the X-ray band from 0.1 to 10 keV (1.2 to 120 A). The characteristics and expected performance of the observatory are described.
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  • 168
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    A numerical study of Saturn's F-ring (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The short term effects of 'shepherding' satellites is examined in the general case where all bodies move along eccentric orbits by analyzing the motion of a ring of particles as their orbits evolve under the gravitational perturbations of the shepherds. This computational approach makes ring evolution calculations extremely efficient numerically, and provides added insight into the nature of this two-body interaction. The procedure is analyzed and applied to several possible configurations of ring and shepherd orbits, emphasizing the F ring. If the F ring-to-satellite distance changes significantly due to eccentricities, the ring can break up into periodic clumps in an azimuthal domain which trails the satellite. This region may lag somewhat in longitude. The perturbations may cause the ring to vary significantly in a width, and can impart a significant, but probably time-variable, eccentricity to the ring.
    Keywords: ASTRONOMY
    Type: Icarus; 52; Dec. 198
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  • 169
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    Possible occulations by satellites of Uranus and Neptune - 1983-1985 (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Predictions are presented for 15 possible occulations by the satellites of Uranus and Neptune from 1983 through 1985. Umbriel, the third satellite of Uranus, might occult a 10.4-mag star (Hyd-20 deg 51699) on 25 March 1983 which will be occulted by Uranus 14 hr earlier. Uncertainties in star positions and ephemerides of planets and satellites are quite large in comparison to the size of these bodies, and these predictions are to be taken as possibilities only.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 87; Dec. 198
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  • 170
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    Infrared properties of serendipitous X-ray quasars (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: (Previously announced in STAR as N83-10995)
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 87; Dec. 198
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  • 171
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    Availability of IMP-J (IMP 8) interplanetary field and plasma data for the International Magnetospheric Study period (IMS) (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The availability of a data set of IMP-J (IMP 8) field and plasma data is announced. Magnetic field data and plasma data from a Faraday cup experiment are provided.
    Keywords: ASTRONOMY
    Type: NASA-TM-85226 , NAS 1.15:85226 , NSSDC/WDC-A-R/S-82-28
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  • 172
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    The structure, energy balance, and winds of cool stars (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Solar magnetic field phenomena which occur in cool stars are summarized. Factors which can produce magnetic fields in stars are listed. Information on cool star atmospheres, provided by high dispersion spectra, is discussed. These spectra show that in Beta Dra (G2 Ib) the transition lines are red shifted (an antiwind), perhaps indicating downflows in closed magnetic flux tubes, as seen in the solar flux tubes above sunspots. The G and K giants and supergiants are classed as active, quiet, or hybrid, depending on whether their atmospheres are dominated by closed magnetic flux tubes, open field geometries, or a predominantly open geometry with a few closed flux tubes embedded.
    Keywords: ASTRONOMY
    Type: ESA 3rd European IUE Conf.; p 3-14
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  • 173
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    High resolution EUV spectroscopy of 56 Pegasi (KO 2p + wd) (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The hypothesis that X-ray and UV emission by 56 Pegasi (K0II p + wd) originates in a conventional chromosphere, transition region and corona, as opposed to Schindler's hypothesis of accretion of the cool stellar wind onto the white dwarf companion, is discussed. Analysis of IUE data indicates that within the uncertainties associated with determining the stellar radius and abundances, the chromosphere, transition region, and corona of 56 Peg are similar to that of Beta Draconis both in structure and energy balance. The accretion hypothesis is not a unique explanation of the observed spectral properties and the white dwarf companion may not play a direct role. Furthermore, 56 Peg, according to current values of V-R and luminosity class, is on the nonsolar side of the Linsky-Haisch dividing line whereas Beta Draconis is on the solar side.
    Keywords: ASTRONOMY
    Type: ESA 3rd European IUE Conf.; p 161-164
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  • 174
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    Far infrared supplement: Catalog of infrared observations (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The development of a new generation of orbital, airborne and ground-based infrared astronomical observatory facilities, including the infrared astronomical satellite (IRAS), the cosmic background explorer (COBE), the NASA Kuiper airborne observatory, and the NASA infrared telescope facility, intensified the need for a comprehensive, machine-readable data base and catalog of current infrared astronomical observations. The Infrared Astronomical Data Base and its principal data product, this catalog, comprise a machine-readable library of infrared (1 micrometer to 1000 micrometers) astronomical observations published in the scientific literature since 1965.
    Keywords: ASTRONOMY
    Type: NASA-TM-84001 , NAS 1.15:84001
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  • 175
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    IUE observations of Herbig-Haro and related objects (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The I.U.E. spectra of the Herbig-Haro objectives H-H 1, H-H 2H, H-H 2G and H-H 32 A are considered. In order to obtain a better understanding of the physics of these intriguing objects and of the formation of the ultraviolet continua and emission lines in H-H objects, the UV spectra of the Cohen-Schwartz star, the T Tauri star AS 353A, and of the reflection nebula NGC 1999 (which is illuminated by the young object V 380 Orionis), are also examined.
    Keywords: ASTRONOMY
    Type: NASA-CR-169367 , NAS 1.26:169367
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  • 176
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    OH fluorescence in comets - Fluorescence efficiency of the ultraviolet bands (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The present investigation is concerned with the calculation of the fluorescence efficiency of OH over a wide range of heliocentric radial velocities. Three vibrational states in each of the two lowest electronic states are included in these calculations, producing a total of nine vibrational bands in the ultraviolet. The attempt is made to reproduce observed, ultraviolet, cometary spectra of OH by utilizing the Swings fluorescence mechanism. The inclusion of four rotational states within each of the three vibrational states and a detailed solar atlas make it possible to match observations very well, although there remain some discrepancies. This ability to reproduce observations provides confidence that the more general results obtained for the fluorescence efficiency as a function of heliocentric radial velocity can be used in interpreting both previous and future observations of OH in comets.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 258
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  • 177
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    Far-infrared observations of FU Orionis (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The peculiar star FU Orionis is located in the southeast extension of Barnard 35 (B35), a bright-rimmed molecular cloud, and in the more extended, low-density region around Lambda Orionis. In connection with the present investigation, far-infrared observations of the star were undertaken in order to obtain a better estimate of the total luminosity of FU Ori and to better understand its relationship with the B35 cloud. FU Orionis was observed on 1981 January 23 with the 90 cm telescope on board the NASA Kuiper Airborne Observatory. The far-infrared results suggest that much of the radiation from the stellar source does not interact with either the 225 K circumstellar dust or the exterior 15 K material. The total luminosity of FU Ori is now seen to be about the same as the visible luminosity, and at the distance to B35 ridge dilution would make any isotropic effects negligible.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 258
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  • 178
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    The Crab Nebula. I - Spectrophotometry of the filaments (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Relative line intensities in the 3700-7400 A region are obtained from new spectrophotometric measurements of ten positions in the Crab Nebula. O III forbidden line intensities imply electron temperatures of 11,000-18,300 K, while generally lower temperatures are indicated by the O II, N II and S II forbidden lines. The 6717 and 6731 A forbidden S II line ratio yields electron density estimates of 550-3500/cu cm, with a typical filament value of 1300 cu cm. While Balmer decrements are generally consistent with pure recombination, some filaments show steeper decrements. He line intensities are found to have significant variation. The presence of a moderately strong line at 7378 A, which may be due to the Ni II forbidden line is confirmed. Some filaments are found to exhibit a wide range of ionization states.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 258
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  • 179
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    International ultraviolet explorer observations of Hyades stars (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: A description is presented of International Ultraviolet Explorer (IUE) satellite observations of transition region and chromospheric emission from a group of Hyades dwarfs which are strong X-ray emitters as seen in a survey conducted by Stern et al. (1981). Short-wavelength spectra (1175-2000 A) and long-wavelength spectra (1900-3200 A) have been obtained. Although the IUE sensitivity limit did not make it possible to detect emission lines in three stars, the presence of chromospheres and transition regions could be confirmed in BD +15 deg 640, 70 Tau, BD +14 deg 693, and BD +16 deg 592. The differential emission measure has been plotted as a function of temperature for the four considered stars.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 258
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  • 180
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    Far-infrared observations of Sagittarius A - The luminosity and dust density in the central parsec of the Galaxy (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Far-infrared observations of the central 4 arcmin of the Galaxy with 30-arcsec resolution made simultaneously at 30 microns, 50 microns, and 100 microns are presented. The 30-micron radiation peaks strongly at the position of the galactic center, as determined from the 2-micron surface brightness and the density of ionized gas. The 50- and 100-micron emission is much more extended along the plane and shows two emission lobes, one on either side of the 30-micron peak. At the position of the galactic center itself there is a local minimum in the 100-micron surface brightness. It is concluded that the dust density decreases inward over the central few parsecs of the Galaxy and that the dust density in the central parsec is so low that optical and ultraviolet radiation freely traverses this region. The total luminosity of the sources heating the dust which radiates the far-infrared emission from the central few parsecs is deduced to be between 1 x 10 to the 7th and 3 x 10 to the 7th solar luminosities.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 258
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  • 181
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    The Copernicus ultraviolet spectral atlas of Beta Orionis (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: An ultraviolet spectral atlas is presented for the B8 Ia star Beta Orionis, which has been scanned from 999 to 1561 A by the Princeton spectrometer aboard the Copernicus satellite. From 999 to 1420 A the observations have a nominal resolution of 0.05 A. At the longer wavelengths the resolution is 0.1 A. The atlas is presented in graphs. Lines identified in the spectrum are also listed.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal Supplement Series; 49; July 198
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  • 182
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    Star formation in the M17 SW giant molecular cloud (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The first high-sensitivity, high-resolution far-IR survey of an entire molecular cloud complex is presented. The 20 km/s M17 SW complex, in addition to the three luminous M17 sources, contains 10 sources spread over 110 pc. The 10 lower luminosity sources divide into two groups: small blister sources powered by late O stars and compact sources powered by clusters of early B stars. No compact far-IR sources with luminosities between the detection limit and 10,000 solar luminosities were detected. Three possible formation mechanisms for the stars that power the far-IR sources in the M17 SW complex are examined. Sequential formation cannot explain the sources seen throughout the complex. Some type of stochastic formation mechanism or collapse induced by a spiral density wave could explain the observations.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 257
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  • 183
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    A multiwavelength study of the AM Herculis type binary 2A 0311-227 (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Keywords: ASTRONOMY
    Type: Royal Astronomical Society; vol. 199
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  • 184
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    Einstein observations of the confused 2A 2315-428 region (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Four distinct X-ray sources have been detected by the Einstein Observatory imaging proportional counter in the 2A2315-428 field. The strongest source in the 0.2-3.8 keV band is associated with the Sersic 159-03 cluster, which contains a cD galaxy, and may account for as much as 40% of the observed 2A flux. The rest of the flux is suspected to issue from the weaker but more heavily cut-off galaxy NGC 7582. It is suggested that such a large X-ray absorption column density in NGC 7582 may account for the absence of a broad H-alpha emission component, as has been observed in other narrow-line X-ray galaxies. The weak X-ray flux from NGC 7552 shows together with a reanalysis of previous observations, that the source is not variable, that its X-ray emission is not likely to result from a compact nucleus, and that it may be a starburst galaxy.
    Keywords: ASTRONOMY
    Type: Royal Astronomical Society; vol. 200
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  • 185
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    Results from the Orbiting Astronomical Observatory. XLI - Photometry of M31 and M33 (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Filter photometry observations from the Orbiting Astronomical Observatory, in six wavelength bands between 1550 and 4250 A, are reported for several positions along the major and minor axes in M31 and at some positions in M33. The spatial resolution is 10 arcmin. The colors along the major axis of M31 within about 20 arcmin of the nucleus are similar to the nucleus; at 45 arcmin the colors are much bluer, indicating a spiral arm population. This behavior is expected from other observations of H I, CO, and early-type stars, which are all concentrated in a ring of material whose inner edge is about 7 kpc (= 35 arcmin) from the nucleus. The center of M33 is bluer than the ring of M31, and the arms of M33 even bluer. There are no colors too blue to be explained (within observational error) by unreddened B stars.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 87; June 198
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  • 186
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    Einstein X-ray observations of QSO's with absorption-line systems (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The detection of X-ray emission from eight QSO's is reported, plus an upper limit to the X-ray flux from one QSO, using the Einstein X-ray Observatory (HEAO-2). Each object in the sample contains at least one absorption-line system that has been identified in its optical spectrum. The present results are combined with those of other investigators to form a sample of 44 absorption-line QSO's (with 2 sub e greater than 1.2) which have been observed in the X-ray. This sample cannot be distinguished, in terms of X-ray properties, from one which consists of QSO's in which no absorption systems have been identified. These results are consistent with extrinsic models for absorption-line clouds, as well as with current versions of intrinsic models.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 87; June 198
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  • 187
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    uvby photometry in McCormick proper motion fields (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The Danish 50 cm telescope at the European Southern Observatory was used to obtain high-precision uvby photometry for 50 F2 to G2 stars, with V values in the 9.4-12.3 mag range, which were selected in the southern galactic polar regions of the McCormick proper motion fields and measured on six different nights. The brighter stars are found to systematically exhibit smaller m(1) indices, of about 0.02 mag, upon comparison with the earlier data of Blaauw et al (1976). Single measurements are given for 98 stars in eight McCormick fields at intermediate southern galactic latitudes.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics Supplement Series; 48; June 198
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  • 188
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    A multiwavelength comparison of Cassiopeia A and Tycho's supernova remnant (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: A comparison of high resolution radio, optical, and X-ray images of two young supernova remnants (SNR), Cas A and Tycho, shows significant differences between them. Cas A probably broke into many small knots at the time of the initial explosion, whereas Tycho's SNR appears to be a more uniformly expanding blast wave.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 257
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  • 189
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    IUE observations of the peculiar star RX Puppis (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The first set of high-dispersion UV observations of RX Pup are presented. Anomalous line profile structure observed in a number of high-excitation emission lines is discussed in context with a model that includes streams and complex mass motions in the system. Anomalies in high-excitation lines suggest dynamic activity in circumstellar material that probably has the form of rings and/or gas streamers between the cool giant and the hot companion. The continuum in low dispersion is fairly flat around 1200-2000 and rises toward longer wavelengths, and cannot be due to a star earlier than A0 II. Alternatively, it may be from an accretion disk. Photoionizing radiation may be due to the presence of an unseen, hot subdwarf with most probable effective temperature 75,000-90,000 K. Alternatively, it may be due to an accretion disk around a secondary with boundary layer temperature about 100,000 K.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 257
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  • 190
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    X-ray observations with the Einstein Observatory of emission-line galaxies (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: X-ray observations of narrow-emission-line galaxies are presented and discussed. One source, NGC 1365, is found to be extended in the soft X-ray band; three others, NGC 2992, NGC 5506, and NGC 7582, have been observed to vary in intensity. The best fit spectral index and cutoff energy E sub a are derived for NGC 2992, NGC 5506, and NGC 7582. The X-ray spectra of these galaxies are similar to those of type 1 Seyfert galaxies. In the case of NGC 5506 and NGC 7582, the absorbing column N sub H derived is about one order of magnitude greater than predicted from the reddening of thy optical continuum and of the Balmer lines. Possible explanations for the discrepancy are discussed.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 257
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  • 191
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    Detection of neutral hydrogen emission and optical nebulosity in the low redshift QSO 0351+026 (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Spectroscopy, photometry, and imaging of the X-ray source 0351+026 are consistent with an active nucleus with the spectrum of a QSO or type I Seyfert, embedded in a low luminosity host galaxy of colors similar to M31. The H I observations reveal a tremendous amount of neutral gas associated with the system, M(H I)/L(B) = 15 in solar units, and the velocity width of the feature is 1500 km/s. Both parameters substantially exceed those seen in other galaxies and interacting pairs. The unique H I properties of the system combined with the presence of an active nucleus with QSO-like features is a tantalizing, but poorly understood, combination. At slightly larger redshift and thus inferior angular scale, this object would be indistinguishable from a QSO in its optical and X-ray characteristics.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 257
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  • 192
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    Identification of resonance features within the rings of Saturn (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: The Voyager 2 UV spectrometer observed a stellar occultation by the rings of Saturn, which located ring features with an accuracy of 12 km. A high-resolution (3 km) optical depth atlas of the rings shows at least nine features, including four density wave patterns, identified with satellite resonances. Analysis of these density wave patterns yields the first surface mass densities for the A ring and, together with the optical depth atlas, a total ring mass of 6.4 x 10 to the -8th Saturn masses.
    Keywords: ASTRONOMY
    Type: Nature; 297; May 13
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  • 193
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    HR 7275 - A new variable star (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Three years of photometry in V and B of the UBV system are presented to confirm the suspicion of Herbst (1973) that HR 7275 is a variable star. The photometry is used to derive the photometric period, which proves to be about 3% shorter than the spectroscopically determined optical period of 28.59 d. Total variation observed during the three years was 0.22 m in the V, and the light curve was always asymmetrical.
    Keywords: ASTRONOMY
    Type: Astrophysics and Space Science; 83; 1-2,; Apr. 198
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  • 194
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    A new, fast X-ray pulsar in the supernova remnant MSH 15-52 (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A pulsing X-ray source has been discovered within the shell of the supernova remnant MSH 15-52. The period is 0.150 s, and the rate of increase of period with time is the highest measured for any pulsar. These characteristics and the fact that the pulsar is surrounded by a small, bright nebula indicate that this object is very similar to the Crab pulsar.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 256
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  • 195
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    Ultraviolet, visual, and infrared observations of the WC7 variable HD 193793 (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Low-resolution IUE data are used to explore the ultraviolet extinction toward the Wolf-Rayet star HD 193793 and to search for ultraviolet variability that might relate to the infrared variability. High-dispersion IUE observations are used to investigate the nature of the stellar wind of the star and to search for anomalies in the interstellar line spectrum that might be expected to be found toward a star that has recently formed a dust shell. Finally, the ultraviolet and new visual and infrared data are combined to investigate the full energy distribution of this unusual source. The energy distribution is found to extend from 0.12 to 12.5 microns, and the ultraviolet data suggest a normal WC-7 type star. A wind terminal speed of about 3000 km/s is implied by the data, as well as an E(B-V) value of 0.85. The dereddened ultraviolet to visual energy distribution is consistent with a star having effective temperature of about 43,000 K.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 256
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  • 196
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    X-ray observations of peculiar galaxies with the Einstein Observatory (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The results of X-ray observations with the Einstein Observatory of 33 galaxies are presented. Almost all of these galaxies, some of which lie in groups and in interactive pairs, display disturbed morphologies. No uniform, well-defined selection criterion can describe the sample galaxies, but almost all lie in a region of the optical color/color diagram that suggests that they are experiencing bursts of star formation. This region is compatible with the locus of Markarian galaxies. The observed sample and the X-ray data are presented, and the X-ray data are discussed and compared with the optical and radio properties of the galaxies. It is concluded that nuclear activity is not the predominant source of X-rays in late-type peculiar galaxies and that the X-ray emission is likely to originate from the Population I galactic component, in particular binary sources and possible young SNR's.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 256
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  • 197
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    2.3-GHz accurate positions and optical identifications for selected Parkes radio sources (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Accurate radio positions of 74 extragalactic radio sources contained in the Parkes 2.7-GHz survey were measured at 2.3 GHz with the Tidbinbilla interferometer, located near Canberra, Australia. The radio sources, most of which lie between declinations -30 deg and -35 deg, were measured to an rms positional accuracy of about 3 arcsec relative to a grid of previously identified radio sources. Optical identifications have been made on the basis of positional coincidence alone, without regard to color or morphology, using the UK Schmidt telescope deep IIIa-J sky survey plates. Identifications are suggested and accurate optical positions have been measured for 62 objects brighter than magnitude 22.5 on the IIIa-J plates.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 87; May 1982
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  • 198
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    Infrared /JHK/ photometry of asteroids (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: We report JHK (1.2, 1.6, and 2.2 micron) photometry for 23 asteroids of various spectral types. All of the TRIAD asteroid classes were sampled. The C and S classes have distinct, infrared color domains. Most R-class asteroids fall within the S-color domain and the observed M asteroids fall within the C-color domain. The E asteroids have neutral colors. Asteroid 446 Aeternitas was discovered to have an unusual J-H color (0.88 mag).
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 87; May 1982
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  • 199
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    Throughput of diffraction-limited field optics systems for infrared and millimetric telescopes (1982)
    In:  Other Sources
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    Publication Date: 2019-06-28
    Description: Telescopes for submillimeter wavelengths have point spread functions some millimeters or centimeters in diameter, but the detectors may be only fractions of a millimeter in size. Thus a field aperture and collecting optics are needed. Optimizing the aperture by a calculation of the effects of diffraction on signal and resolution as a function of size of the collecting aperture is shown. Calculations are compared to experimental results from observations of Mars at submillimeter wavelengths.
    Keywords: ASTRONOMY
    Type: Applied Optics; 21; May 15
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  • 200
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    The diameter of 88 Thisbe from its occultation of SAO 187124 (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The 7 October, 1981 occultation of SAO 187124 by 88 Thisbe was observed at twelve sites. The occultation observations, together with information about the asteroid's light curve, gives a mean diameter for Thisbe of 232 + or - 10 km. This value is 10 percent larger than the previously published radiometric diameter of Thisbe.
    Keywords: ASTRONOMY
    Type: NASA-CR-169312 , NAS 1.26:169312
    Format: application/pdf
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