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  • Other Sources  (731)
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  • 101
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    Observations of Paschen alpha in the broad-line radio galaxy 3C 445 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: P alpha line flux measurements of the broad-line radio galaxy 3C 445 made at the NASA IR Telescope Facility in September 1981 are discussed. Broad-band measurements were obtained at H of 1.65 micron and K of 2.2 microns. A line flux of P alpha was found at 3.4 times 10 to the -13th ergs/sq cm sec. No discernable variation was detectable regarding measurements made in 1976. Substantial reddening was concluded to exist, although the H gamma lines observed were not due to reddening. The total H alpha luminosity was determined to be 4 x 10 to the 43rd ergs/sec. Steep Balmer line decrements are concluded to be due to interposed dust.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 256
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  • 102
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    HEAO 1 measurements of the galactic ridge (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-20097)
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 255
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  • 103
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    Comparison of starting values for iterative solutions to a universal Kepler's equation (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: General starting values for the iterative numerical solution of a universal Kepler's equation for position in a conic orbit at a specified time are investigated. Three starting values based on recent refinements of previously obtained bounds on the solution are derived and tested numerically. Of these, a simple starting value based on a cubic approximation to Kepler's equation provides the most rapid convergence using both first and second order Newton algorithms. The performance of the starting values are compared with similar studies which used the restricted case of elliptical orbits with the initial epoch at periapse.
    Keywords: ASTRONOMY
    Type: Journal of the Astronautical Sciences; 30; Jan
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  • 104
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    Radial widths, optical depths, and eccentricities of the Uranian rings (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Observations of the stellar occultation by the Uranian rings of 15/16 August 1980 are used to estimate radial widths and normal optical depths for segments of rings 6, 5, 4, alpha, beta, eta, gamma, and delta. Synthetic occultation profiles are generated to match the observed light curves. A review of published data confirms the existence of width-radius relations for rings alpha and beta, and indicates that the optical depths of these two rings vary inversely with their radial widths. Masses are obtained for rings alpha and beta, on the assumption that differential precession is prevented by their self-gravity. A quantitative comparison of seven epsilon-ring occultation profiles obtained over a period of 3.4 yr reveals a consistent structure, which may reflect the presence of unresolved gaps and subrings.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 87; Feb. 198
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  • 105
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    Vacuum deposition of iridium on large astronomical mirrors for use in the far UV (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An iridium coating has been deposited by electron-beam evaporation on a 0.91-m mirror which serves as the telescope primary of a sounding rocket instrument for far-UV spectrometry. The evaporation was carried out by applying 8 kV at 400 mA to the electron gun. Zone refined Ir of 99.99% purity was used, and the electron beam was electromagnetically swept over the surface of the evaporant. Under these conditions, deposition rates of 0.55 A/sec were achieved. The reflectance distribution achieved at a wavelength of 584 A was extremely uniform; the mean reflectance was 21.2% with a standard deviation of only 0.3%. This represents a substantial improvement over Al + MgF2 and Al + LiF coatings for applications involving multiple reflections and weak signals, as might be expected in a high-resolution spectrograph studying distant celestial objects.
    Keywords: ASTRONOMY
    Type: Applied Optics; 21; Jan. 1
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  • 106
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    Current NASA studies for a Far Ultraviolent Spectrographic Explorer (FUSE) (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The NASA plans for FUSE, a satellite which obtains spectra with resolutions between 100,000 and 100 in the spectral regions from 912 to 1216A and 100 to 912A, are outlined. Scientific problems which can be tackled by FUSE, but not by IUE or the Space Telescope, are discussed. A grazing incidence echelle and a hybrid echelle design are presented. They have high throughput, large simultaneous spectral range, and low background photon counting statistics. The satellite operational organization is similar to that of IUE.
    Keywords: ASTRONOMY
    Type: ESA 3rd European IUE Conf.; p 473-485
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  • 107
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    The observed properties of X-ray pulsars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A unified description of the properties of the 14 X-ray pulsars is summarized. Properties of X-ray pulsars and obvious correlations with luminosity are outlined.
    Keywords: ASTRONOMY
    Type: Max-Planck Inst. Phys. and Astrophys. Accreting Neutron Stars; p 29-40
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  • 108
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    The interstellar spectrum of the supernova 1980k in NGC 6946 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Bright supernovae in external galaxies offer a rare opportunity to probe the intervening interstellar media over very extended path-lengths, including the disk and halo of the Galaxy and the parent galaxy of the supernova. SN 1980k was discovered in NGC 6946 on 1980 October 29. In the first month after discovery, high resolution optical and ultraviolet observations were obtained to exploit the supernova as a probe of the intervening interstellar media. The obtained data are discussed. In the spectra, absorption lines were observed of Mg I, Mg II, Fe II, Mn II, Ca II and Na I. The absorption lines are attributed to the intervening interstellar media distributed over the very extended line of sight sampled, of order 7 Mpc. These lines are wider and stronger than any previously measured in the quiescent interstellar gas in the halo and disk of the Milky Way and of external galaxies
    Keywords: ASTRONOMY
    Type: Royal Astronomical Society; vol. 199
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  • 109
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    Observation of two gamma-ray bursts by Vela X-ray detectors (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Bursts of X-rays coincident in time with two gamma-ray burst events were observed by the 3-12 keV collimated X-ray detectors on the Vela spacecraft. Both of these observations show recurrence on a time scale of hundreds of seconds. For one of these events (GB 720514) the X-ray detection gives an improved position as well as information on the spectrum late in the outburst. The other event (GB 740723) is of special interest because the source, not previously located, is consistent in direction with the binary pulsar SMC X-1 in the Small Magellanic Cloud; this is the first moderately small error box for a gamma-ray burst to contain a strong X-ray source.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 254
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  • 110
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    The ultraviolet spectrum of the Crab Nebula (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Ultraviolet spectroscopy of the Crab Nebula done by the International Ultraviolet Explorer satellite is described, and an estimate of the carbon abundance is made, noting data reduction to remove spectral defects caused by radiation hits. The important C IV 1549, He II 1640, and semiforbidden C III 1908 emission line intensities were measured and upper limits placed on other ultraviolet features for the brightest filamentary region in the Nebula. The emission lines imply an average ionic abundance ratio n(C+2)/n(O+2) in the range from 0.4 to 1.5 in the observed gaseous condensations. The elemental abundance ratio of carbon to oxygen is probably in the same range. Analysis shows that there is no perceptible excess of carbon due to presupernova nucleosynthesis in the observed region. The large helium abundance, small carbon and oxygen abundances, and presence of a neutron star in the Crab Nebula suggest that the presupernova star had a mass close to eight solar masses.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 253
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  • 111
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    Properties of young clusters near reflection nebulae (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Near infrared observations in the reflection nebulae NGC 703, 2023, and 2068 are used to study clusters of young stars found associated with these nebulae. At least 30 percent to 60 percent of these stars are pre-main sequence objects, as indicated by their infrared excesses, hydrogen line emission, or irregular variability. The spatial distributions and observed luminosity functions of these young open clusters are derived, and the inferred mass function and star formation efficiencies are discussed. Previously announced in STAR as N83-25628
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 88; July 198
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  • 112
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    Cometary impacts with the sun - Physical and dynamical considerations (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Michels et al. (1982) observed the apparent impacting of the sun by a comet, and Sekanina (1982) showed that the comet, 1979XI, was probably a member of the Kreutz group of sun-grazing comets, although its perihelion of 0.35 solar radii was much smaller than the 1.2-1.9 solar radii common for this comet class. The perihelion change cannot be explained by planetary, stellar, or nongravitational perturbations. The most plausible explanation is collision with another body, probably a comet, at large heliocentric distance. The probability of such an event is, however, extremely small. The sublimation of the comet's nucleus before impact is discussed, and it is suggested that its ultimate destruction probably resulted from the shock of entry into the denser regions of the solar atmosphere, just above the photosphere.
    Keywords: ASTRONOMY
    Type: Icarus (ISSN 0019-1035); 55; Sept
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  • 113
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    An infrared study of the eclipsing dwarf nova U Geminorum (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: One series of data comprising the present J, H, K broadband IR photometry of the cataclysmic binary system U Geminorum over the course of two orbital cycles was obtained several days before an outburst, while a second was gathered when the system had almost completely returned to quiescence from that outburst. In quiescence, the M4-M5.5 red dwarf star supplies most of the IR luminosity of the system, while the light curves at this time are tidally induced ellipsoidal variations of the red dwarf which exhibit an amplitude such that the red dwarf must fill, or nearly fill, its Roche lobe. This shows directly that Roche lobe overflow is important in cataclysmic variable stars. The range of the disk IR colors after outbursts suggest that cool and optically thick gas, together with optically thin gas, supply most of the IR light of the disk.
    Keywords: ASTRONOMY
    Type: Royal Astronomical Society, Monthly Notices (ISSN 0035-8711); 204; Sept
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  • 114
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    Very large spiral galaxies (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: As a first step in the systematic study of large spirals, which may be useful in cosmological tests and studies of galaxy evolution, a catalog of the 107 largest known spiral galaxies is presented. Catalog galaxies have isophotal diameters greater than 90 kpc, assuming an H(zero) value of 50 km/sec per Mpc. UBVR photoelectric photometry is presented for 20 of these galaxies, and absolute magnitudes are derived for all galaxies in the catalog by transforming Zwicky magnitudes to the B(T) system.
    Keywords: ASTRONOMY
    Type: Royal Astronomical Society, Monthly Notices (ISSN 0035-8711); 204; Sept
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  • 115
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    Further studies on criteria for the onset of dynamical instability in general three-body systems (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Numerical experiments designed for the elucidation of the conditions under which self-gravitating, three-body systems become dynamically unstable are examined of the cases of four orbital configuration types: circular, prograde, and coplanar; circular, retrograde, and coplanar; circular, direct, and inclined; and eccentric, direct, and coplanar. Results indicate that orbital inclination does not significantly affect stability in 'outer planet' configurations, while the stability of 'inner planet' configurations, where the tertiary is in close orbit about one member of the binary, is markedly less affected, once the relative orbital inclination is greater than 50 deg. It is found that the onset of dynamical instability is only weakly dependent on the eccentricity of either the binary or tertiary orbit, as long as the mass of the tertiary is comparable to the reduced mass of the binary.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 88; Sept
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  • 116
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    DE 102 - A numerically integrated ephemeris of the moon and planets spanning forty-four centuries (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: It is pointed out that the 1960's were the turning point for the generation of lunar and planetary ephemerides. All previous measurements of the positions of solar system bodies were optical angular measurements. New technological improvements leading to immense changes in observational accuracy are related to developments concerning radar, Viking landers on Mars, and laser ranges to lunar corner cube retroreflectors. Suitable numerical integration techniques and more comprehensive physical models were developed to match the accuracy of the modern data types. The present investigation is concerned with the first integrated ephemeris, DE 102, which covers the entire span of the historical astronomical observations of usable accuracy which are known. The fit is made to modern data. The integration spans the time period from 1411 BC to 3002 AD.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics (ISSN 0004-6361); 125; 1, Au; Aug. 198
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  • 117
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    The IRAS telescope (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The IRAS telescope is described in terms of its system configuration and physical characteristics, subsystem functions and descriptions, and performance characteristics. The mission and the configuration are reviewed briefly, and the major functional components of the telescope are described, including the focal plane assembly, the optics, the electronics, the cryogenics, and the thermal control. Exploded and cross-sectional views and block diagrams are presented for the telescope system configuration, focal plane assembly, infrared subarray module, optical subsystem, infrared channel data flow, and main cryogen dewar. The telescope physical characteristics are listed. The performance characteristics are listed and discussed, including the spectral response, sensitivity, optical quality, and photometric accuracy. Relative system spectral response curves for the infrared bands are shown.
    Keywords: ASTRONOMY
    Type: vol. 36; Jan. 198
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  • 118
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    Development of a 1m-normal-incidence-EUV-Telescope (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A brief description is given of the 1m-EUV-Telescope and its focal plane instrumentation, namely an EUV spectrometer and six EUV/FUV photometers. The telescope is scheduled for launch on an Aries rocket on June 17, 1982. The principal goals are the white dwarf HZ43 and a photometric scan across the sky in an area of the sky where 21 cm line observations reveal a steep density gradient. The optical bench of the telescope is a cylinder made of a graphite epoxy compound. Despite its low specific weight, the bench shows an excellent mechanical performance, with an elasticity modulus of approximately 70,000 N/cu mm. It is pointed out that by carefully combining layers with different winding angles of the carbon fiber, the thermal expansion along the cylinder axis is almost negligible, even under severe thermal loads
    Keywords: ASTRONOMY
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  • 119
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    Coordinate systems (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Jovian coordinate systems are different from those employed in the case of the earth. Latitude and longitude coordinates are usually established relative to some solid surface. Because Jupiter does not have a solid surface (at least none which is visible through the clouds), arbitrary, but convenient, coordinate grids have been prescribed. A spin equator is made out from observations of cloud motion, and the direction of the planetary spin axis is, therefore, determined with relatively good accuracy. The problem in establishing a Jupiter longitude system is that the mean rotation period of the clouds is a function of latitude. The solution selected was to define two separate longitude grids. A third longitude system became necessary with the detection of radio signals which gave evidence for a rotating planetary magnetic field. Attention is also given to orbital phase angle and longitude conventions for satellites, and two latitude systems for Jupiter
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  • 120
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    Transformations of the perturbed two-body problem to unperturbed harmonic oscillators (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Singular, nonlinear, and Liapunov unstable equations are made regular and linear through transformations that change the perturbed planar problem of two bodies into unperturbed and undamped harmonic oscillators with constant coefficients, so that the stable solution may be immediately written in terms of the new variables. The use of arbitrary and special functions for the transformations allows the systematic discussion of previously introduced and novel anomalies. For the case of the unperturbed two-body problem, it is proved that if transformations are power functions of the radial variable, only the eccentric and the true anomalies (with the corresponding transformations of the radial variable) will result in harmonic oscillators. The present method significantly reduces computation requirements in autonomous space operations.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics (ISSN 0008-8714); 30; May 1983
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  • 121
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    Revised orbits for 105 Herculis and Pi Cephei A and a model for the Pi Cephei system (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: New orbital elements for the giant primary components of 105 Herculis and Pi Cephei A are derived using radial velocities from Dominion Astrophysical Observatory coude plates. These data are combined with those of Harper (1925) in order to estimate the velocity amplitude of Pi Cephei A in the visual orbit of this triple system. Two models of this system are developed. In the first model, the unseen spectroscopic secondary component is a single main-sequence star, although this seems unlikely, while in the alternative model the unseen secondary component is itself double.
    Keywords: ASTRONOMY
    Type: Royal Astronomical Society; vol. 203
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  • 122
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    Lunar luminescence measurements (1983)
    In:  CASI
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    Publication Date: 2016-06-07
    Description: Spectra of lunar sites obtained in June 1983 have been analyzed for residual luminescence using the spectral line depth technique. The results or three sites each at three wavelengths are presented. The sites observed were Mare Crisium, Kepler, and Aristarchus. In each case, the value quoted was based not only on the strong Fraunhofer line in the spectral range covered but also on from 11 to 21 weaker lines within 80 A of the strongest feature. These data do not support previous observations. The values given do not indicate a greatly reddened spectrum, and the luminescence spectrum of the mare site is not significantly different from the two young crater sites. These observations cannot be adequately explained by thermal luminescence, theories of direct excitation are also unable to explain the strength of the flux.
    Keywords: ASTRONOMY
    Type: NASA. Johnson (Lyndon B.) Space Center The 1983 NASA/ASEE Summer Faculty Fellowship Research Program Research Reports; NASA. Johnson (Lynd
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  • 123
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    Radio Astronomy (1983)
    In:  CASI
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    Publication Date: 2014-09-12
    Description: Deep Space Network (DSN) 26- and 64-meter antenna stations were utilized in support of Radio Astronomy Experiment Selection Panel experiments. Within a time span of 10 days, in May 1983 (267.75 hours total), nine RAES experiments were supported. Most of these experiments involved multifacility interferometry using Mark 3 data recording terminals and as many as six non-DSN observatories. Investigations of black holes, quasars, galaxies, and radio sources are discussed.
    Keywords: ASTRONOMY
    Type: The Telecommun. and Data Acquisition Rept.; p 112-113
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  • 124
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    Upper Limits to the Annihilation Radiation Luminosity of Centaurus a (1983)
    In:  CASI
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    Publication Date: 2014-09-10
    Description: A high resolution observation of the active nucleus galaxy Centaurus A (NGC 5128) was made by the GSFC low energy gamma-ray spectrometer (LEGS) during a balloon flight on 1981 November 19. The measured spectrum between 70 and 500 keV is well represented by a power law of the form 1.05 x 10 (-4) (E/100 keV) (-1.59) ph/sq cm /s with no breaks or line features observed. The 98% confidence (2 sigma) flux upper limit for a narrow ( 3 keV) 511-keV positron annihilation line is 9.9 x 10 (-4) ph/ sq cm /s. Using this upper limit, the ratio of the narrow-line annihilation radiation luminosity to the integral or = 511 keV luminosity is estimated to be 0.09 (2 sigma upper limit). This is compared with the measured value for our galactic center in the Fall of 1979 of 0.10 to 0.13, indicating a difference in he emission regions in the nuclei of the two galaxies.
    Keywords: ASTRONOMY
    Type: NASA(Goddard Space Flight Center Contrib. to the Workshop on Positron-Electron Pairs in Astrophys.; p 39-44
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  • 125
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    HD 207739 - A strange composite star (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: This star, classified F8 IIe + B:, has a very unusual ultraviolet spectrum, with abnormally strong and numerous absorption features in the far-UV and exceptionally strong Mg II emission. There is some resemblance to shell and pre-main-sequence B stars, but it more closely matches the strange spectra of the eclipsing systems VV Cep and SX Cas, and it probably has considerable circumstellar material at fairly high temperature. HD 207739 is probably an interacting binary and needs to be monitored for light and velocity variations.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 264
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  • 126
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    Spectroscopic equipment for the Space Telescope (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Space Telescope will provide views of the Universe of remarkable clarity. Central to its capabilities is an f/24 Ritchey-Chretien telescope with 40,000 sq cm unobscured collecting area, which will provide point-source images less than 0.1 sec in radius at wavelengths below 633 nm. It will operate over the range 110 nm to 1 mm. The initial flight instrumentation includes two spectrographs, the Faint Object Spectrograph (F.O.S.) and the High-Resolution Spectrograph (H.R.S.). The F.O.S. is sensitive from 115 to 800 nm. It will provide data at resolving powers 1000-100 on extremely faint sources. The H.R.S. operates at the wavelengths 107-320 nm. It will achieve high photometric accuracy at resolving powers 100,000, in the echelle mode, or 10,000-1000 in first order, on brighter targets. The two cameras on board the Space Telescope will provide ancillary spectroscopic capabilities.
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  • 127
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    Global sensitivity to velocity errors at the libration points (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The global effects on non-linear stability are investigated at and around the triangular libration points. The model of the circular restricted problem of three bodies is used, considering the earth and the moon as the primaries. Areas of the initial conditions in the configuration space leading to stability with zero initial velocity around the equilibrium points are compared to stable areas in the phase space with variable initial velocity and zero initial deviations at the equilibrium points. The behavior of the system concerning errors due to initial conditions in the configuration space is studied for 6 years and the effects of initial velocity errors are considered for 7.73 years.
    Keywords: ASTRONOMY
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  • 128
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    Studies in astronomical time series analysis. II - Statistical aspects of spectral analysis of unevenly spaced data (1982)
    In:  Other Sources
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    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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  • 129
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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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  • 130
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    Time variations in C IV lambda 1550 and Ly alpha emission lines in NGC5548 (1982)
    In:  Other Sources
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    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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  • 131
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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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  • 132
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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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  • 133
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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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  • 134
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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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  • 135
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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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  • 136
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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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  • 137
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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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  • 138
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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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  • 139
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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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  • 140
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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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  • 141
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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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  • 142
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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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  • 143
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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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  • 144
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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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  • 145
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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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  • 146
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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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  • 147
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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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  • 148
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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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  • 149
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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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  • 150
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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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  • 151
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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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  • 152
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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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  • 153
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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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  • 154
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    Abundance fluctuations in the interstellar medium (1982)
    In:  Other Sources
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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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  • 155
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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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  • 156
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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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  • 157
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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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  • 158
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    The nova-like variable KQ Mon and the nature of the UX Ursa Majoris stars (1982)
    In:  Other Sources
    Details
    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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  • 159
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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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  • 160
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    Hydrogen two photon emission in the UV spectrum of type 2 supernovae (1982)
    In:  Other Sources
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    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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  • 161
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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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  • 162
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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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  • 163
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    Observations of the red auroral oxygen lines in nine comets (1982)
    In:  Other Sources
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    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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  • 164
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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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  • 165
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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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  • 166
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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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  • 167
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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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  • 168
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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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  • 169
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    U.S. data processing for the IRAS project (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The JPL's Scientific Data Analysis System (SDAS), which will process IRAS data and produce a catalogue of perhaps a million infrared sources in the sky, as well as other information for astronomical records, is described. The purposes of SDAS are discussed, and the major SDAS processors are shown in block diagram. The catalogue processing is addressed, mentioning the basic processing steps which will be applied to raw detector data. Signal reconstruction and conversion to astrophysical units, source detection, source confirmation, data management, and survey data products are considered in detail.
    Keywords: ASTRONOMY
    Type: vol. 36; Jan. 198
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  • 170
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    Experimental test of the variability of G using Viking lander ranging data (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Results are presented from the analysis of solar-system astrometric data, notably the range data to the Viking landers on Mars. A least-squares fit of the parameters of the solar system model to these data limits a simple time variation in the effective Newtonian gravitational constant to (2 + or - 4) x 10 to the -12th/yr and a rate of drift of atomic clocks relative to the implicit clock of relativistic dynamics to (1 + or - 8) x 10 to the -12th/yr. The error limits quoted are the result of uncertainties in the masses of the asteroids.
    Keywords: ASTRONOMY
    Type: Physical Review Letters (ISSN 0031-9007); 51; 1609-161
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  • 171
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    Astrometry (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Progress in astrometry is reviewed. Aspects of photographic astrometry are addressed, including the use and optimization of emulsions as detectors and the application of side-field and long-focus photographic astrometry to the determination of stellar positions, to proper motion surveys, the determination of more accurate parallaxes, the study of binaries, and the examination of the membership and internal motions of star clusters. The advantages and disadvantages of photoelectric astrometry are summarized, and the instruments used in this field is discussed, including scanners, detector arrays, stellar interferometers, space telescopes, and satellites. Promising observational methods for studying binary stars are addressed. Astrometry derived from meridian circle observations is considered, emphasizing the FK4 system. The use of radio astrometry is briefly discussed.
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  • 172
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    Photoelectric photometry of selected SAO stars. III (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Photometric observations of 131 SAO stars for use in calibrating data obtained from the Near Infrared Photographic Sky Survey (NIPSS) are reported. The serial numbers of the primary NIPSS program fields in which the photometry was done are shown along with the approximate position of each field and the number of stars observed in each field. The observations are listed, showing the SAO numbers of the program stars, their 1950 equatorial coordinates, the V magnitudes, and the (V-R) and (V-I) color indices. The mean errors in magnitudes and color indices obtained by averaging deviations from the mean for each star are on the order of 0.02 mag.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific, Publications (ISSN 0004-6280); 95; 876
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  • 173
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    The unique cometary nebula Parsamian 13 (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Parsamian 13 is found to be a cometary nebula, with a deeply embedded star suffering strong absorption by silicate grains. A feature near 2.7 microns, attributed to absorption by terminal OH groups, may represent the first detection in an astrophysical environment of water ice grains diluted by another molecule, for example by CO. The bolometric luminosity suggests that this star is either an extremely young T Tauri star or an evolved low-mass star, now a red giant, high on its convective track. Most unusual is the presence of cold (50 K) TiO gas in sufficient abundance to show in absorption in the optical and very near-infrared regions; this material probably represents very recently expelled photospheric layers.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 273; 624-632
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  • 174
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    The future of VLBI observatories in space (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The angular resolution of radio maps made by earth-based VLBI observations can be exceeded by placing at least one element of a VLBI array into earth orbit. A VLBI observatory in space can offer the additional advantages of increased sky coverage, higher density sampling of Fourier components, and rapid mapping of objects whose structure changes in less than a day. This paper explores the future of this technique.
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  • 175
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    Radio stars - A possible link between the Hipparcos optical reference frame and an extra-galactic very long baseline interferometry reference frame (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The concept of typing the Hipparcos optical and the JPL VLBI frames of reference by means of VLBI measurements of the positions and proper motions of the radio components of some bright stars is considered. The properties of the thermal and non-thermal radio-stars are discussed and 22 candidate stars are selected to achieve this tie. A description is given of the first VLBI attempt to detect these stars on the intercontinental baselines of the Deep Space Network with the Mark II recording system.
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  • 176
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    Earth rotation from lunar laser ranging (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The rotational orientation (Universal Time and the variation of latitude at McDonald Observatory, Texas) of the earth has been determined between mid 1970 and mid 1982 from McDonald Observatory lunar laser ranging (LLR) data. Universal Time, UT1, is calculated and supplied in three forms, the raw daily decomposition values, the Gaussian filtered values and the Fourier smoothed values. Formal error estimates are available for all three types. LLR can calculate corrections to one component of polar motion, the variation of latitude at McDonald Observatory. Modelling improvements have been applied here and a significant drop is seen in the residuals. The rms weighted residual for the entire thirteen year data span (3,326 'normal' points acquired between August 1969 and May 1982) is 18.7 cm.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics Supplement Series (ISSN 0365-0138); 54; 519-540
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  • 177
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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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  • 178
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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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  • 179
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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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  • 180
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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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  • 181
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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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  • 182
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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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  • 183
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    On the distribution of orbits among long-period comets (1982)
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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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  • 184
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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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  • 185
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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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  • 186
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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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  • 187
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    Ultraviolet observations of four symbiotic stars (1982)
    In:  Other Sources
    Details
    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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  • 188
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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
    Details
    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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  • 189
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    Observations of NGC 604 over six decades in frequency (1982)
    In:  Other Sources
    Details
    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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  • 190
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    A large aperture balloon-borne telescope for a submillimeter wavelength survey of the galactic plane (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: A balloon-borne, 1.2 meter Cassegrain telescope with a servo-controlled chopping secondary mirror has been developed and used to survey the Galactic Plane at submillimeter wavelengths. The telescope pointing system uses a gyroscope as the primary stabilization reference and makes use of microprocessors for pointing control, on-board data collection, and telemetry formatting. A description of the telescope, multi-channel liquid-helium-cooled focal plane and the aspect and orientation subsystems are presented.
    Keywords: ASTRONOMY
    Type: (ISSN 0273-1177)
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  • 191
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    Experimental limits of the extreme ultraviolet background (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Photometric observations of the diffuse extreme ultraviolet background with two photometers having bandpasses of 750-940 A and 1040-1080 A are reported. The payload, which was flown aboard an ARIES sounding rocket in June 1982, is described, including the electron detectors, filters, and calibration. The operation of the probe during the experiment, including its motions, are described. The primary experiment involved spectroscopic observation of the hot white dwarf HZ43. The photometer count rate is shown and the measurements of the diffuse background are compared with theoretical predictions. Despite the lower limits obtained using a narrowband detector, the measurements are not sensitive enough to draw any relevant astrophysical conclusions.
    Keywords: ASTRONOMY
    Type: (ISSN 0374-1958)
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  • 192
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    Five years of photometry of Sigma Geminorum (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Thirteen observatories have collaborated in obtaining five years of photoelectric photometry for the bright, K1 III RS CVn binary Sigma Geminorum. Except for one year, the light curve has exhibited two minima which are separated by approximately half a cycle. At the 1977.2 epoch of discovery one minimum was shallower, but as of 1982.2 they have become comparable in depth. During the 1979-80 season, the light curve changed shape rapidly, with the shallower minimum becoming as deep as the other within a period of no more than 80 days. The overall brightness range during the five years in V has been 4.13-4.29 mag, and it is found that the times of both minima can be fit with a photometric period of 19.423 days.
    Keywords: ASTRONOMY
    Type: Astrophysics and Space Science (ISSN 0004-640X); 93; 2, Ju; June 198
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  • 193
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    Infrared (JHK) photometry of asteroids. II (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: JHK (1.2, 1.6, and 2.2 micron) photometry for 38 asteroids of various spectral classifications is reported. M asteroids tend to have infrared colors intermediate between the color domains of E and P asteroids. A few D asteroids have redder J - H colors than most C asteroids. The unusually red J - H color of 246 Asporina indicates it is a member of the A class.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 88; July 198
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  • 194
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    Massive eclipsing binary candidates (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: New UBV data are provided for 63 southern OB stars which are either identified in the survey by Garrison, Hiltner, and Schild as having double lines or are known from Wood et al. to be eclipsing binaries. Twenty of the stars are known eclipsing variables. Four stars, not previously known as eclipsing, have both spectroscopic evidence of duplicity and significant photometric variations. Several additional stars have a marginally significant spread in V magnitude.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal Supplement Series (ISSN 0067-0049); 52; May 1983
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  • 195
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    Worldwide photometry and lightcurve observations of 16 Psyche during the 1975-1976 apparition (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Twenty-six lightcurves of Psyche are presented together with UBV photometry and phase functions from 1975 and 1976. Combining photometric data from this opposition with those from previous apparitions resulted in a mean phase coefficient in V of 0.026 + or - 0.002 mag/deg. No significant phase-dependent variation in the U-B color could be determined from the data; the B-V color, however, displayed a reddening with phase of 0.0010 + or - 0.0004 mag/deg. It is concluded that compositional variations over Psyche's surface are minor, and that Psyche's opposition effect is typical of that for other well-observed asteroids. Psyche's behavior is accounted for if, to the first order, its shape is that of a triaxial ellipsoid with axial ratios near 5:4:3.
    Keywords: ASTRONOMY
    Type: Icarus (ISSN 0019-1035); 54; April 19
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  • 196
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    Worldwide photometry and lightcurve observations of 1 Ceres during the 1975-1976 apparition (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Lightcurves and UBV photometry of Ceres from the 1975-1976 apparition are presented. The synodic period is 0.37812 + or 0.00004 day, the mean absolute V magnitude is 3.61 + or 0.03, and the phase coefficient is 0.040 + or - 0.001 mag/deg. The U-B and B-V phase coefficients are +0.0015 + or - 0.0007 and +0.0006 + or - 0.0003 mag/deg, respectively. The colors at zero phase are B-V = +0.70 + or - 0.01 and U-B = +0.41 + or 0.01.
    Keywords: ASTRONOMY
    Type: Icarus (ISSN 0019-1035); 54; April 19
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  • 197
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    Pole orientation of asteroid 44 Nysa via photometric astrometry, including a discussion of the method's application and its limitations (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The results of photometric astrometry, a method of determining the orientation of a rotation axis, as applied to asteroid 44 Nysa, are presented. The pole orientation of Nysa was found to be lambda(zero) = 100 deg, beta(zero) = +60 deg with an uncertainty of 10 deg. The sidereal period is 0.26755902 days + or - 0.00000006, and the rotation prograde. Refinements to, and limitations of, the application of the method of photometric astrometry are discussed. In light of the results presented herein, it is believed that all photometric astrometry pole determinations of the past should be redone.
    Keywords: ASTRONOMY
    Type: Icarus (ISSN 0019-1035); 54; April 19
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  • 198
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    Lightcurves and phase function of asteroid 44 Nysa during its 1979 apparition (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Lightcurves of asteroid 44 Nysa obtained during 20 nights in 1979 as part of a global compaign are presented. The synodic period was 6 hours and 25.3 minutes. The phase coefficient of the primary maximum was 0.026 mag/deg and the absolute V magnitude 7.05. The phase function is linear from 2 to 25 deg, no opposition effect is present.
    Keywords: ASTRONOMY
    Type: Icarus (ISSN 0019-1035); 54; April 19
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  • 199
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    Aperture synthesis observations of Orion B at 2.695 and 8.085 GHz (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Interferometer observations of Orion B at 2.695 and 8.085 GHz are presented. Orion B appears to be a double source: one H II region associated with the star NGC 2024 No. 2 and an extended H II region surrounding the star NGC 2024 No. 1. This structure gives support to the model that the stars NGC 2024 No. 2 and No. 1 (of spectral type O 9.5 and B 0.5, respectively) ionize the nebula.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics (ISSN 0004-6361); 120; 2, Ap; April 19
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  • 200
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    Speckle imaging for planetary research (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The present study of speckle imaging technique effectiveness encompasses image reconstruction by means of a division algorithm for Fourier amplitudes, and the Knox-Thompson (1974) algorithm for Fourier phases. Results which have been obtained for Io, Titan, Pallas, Jupiter and Uranus indicate that spatial resolutions lower than the seeing limit by a factor of four are obtainable for objects brighter than Uranus. The resolutions obtained are well above the diffraction limit, due to inadequacies of the video camera employed. A photon-counting camera has been developed to overcome these difficulties, making possible the diffraction-limited resolution of objects as faint as Charon.
    Keywords: ASTRONOMY
    Type: Icarus (ISSN 0019-1035); 53; March 19
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