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  • ASTRONOMY
  • 1985-1989  (219)
  • 1980-1984  (246)
  • 1975-1979
  • 1987  (219)
  • 1980  (246)
  • 1
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    Palomar-Leiden minor planets - Proper elements, frequency distributions, belt boundaries, and family memberships (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Tabulations are presented for the proper elements of 1227 higher accuracy orbits of faint minor planets encompassing earth and deep Mars crossers, Trojans, and Hildas. The distribution of the closest approach distance to Mars drops off sharply near zero, while that for Jupiter vanishes near 1.1 AU; it is suggested that Mars and Jupiter have caused these boundaries, so that the asteroid belt must have been larger early in the solar system's history. Some 3.5 percent of the sample, primarily shallow crossers, can impact Mars; the fortuitous alignments required for impact occur with near-simultaneity for these objects, so that they will episodically bombard Mars.
    Keywords: ASTRONOMY
    Type: Icarus (ISSN 0019-1035); 72; 276-303
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  • 2
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    Ground-based infrared observations of variable IRAS sources as candidates for late asymptotic giant branch stars (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Analysis of the color distribution of OH/IR stars and IRAS low-resolution spectra class 30 objects suggests the presence of a well-defined evolutionary sequence which is populated by late asymptotic giant branch (LAGB) stars. The paper reports ground-based identification and infrared photometry of 10 candidates of news LAGB stars. None of the selected sources are found to have optical counterparts, and eight of the 10 show a strong 10-micron silicate absorption feature. It is suggested that these stars represent an invisible extension of extreme Mira variables and are some of the most evolved stars observed to date.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 321; 975-983
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  • 3
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    Fourier removal of stripe artifacts in IRAS images (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: By working in the Fourier plane, approximate removal of stripe artifacts in IRAS images can be effected. The image of interest is smoothed and subtracted from the original, giving the high-spatial-frequency part. This 'filtered' image is then clipped to remove point sources and then Fourier transformed. Subtracting the Fourier components contributing to the stripes in this image from the Fourier transform of the original and transforming back to the image plane yields substantial removal of the stripes.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 94; 1092-109
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  • 4
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    Identification of a constellation from a position (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A table is presented which permits rapid determination of the constellation in which an object is located from its 1875.0 position. Directions for accessing and using the table are given. The historical background to the table's development is briefly stated.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific, Publications (ISSN 0004-6280); 99
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  • 5
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    Radar astrometry of near-earth asteroids (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: An uncertainty analysis is conducted for four asteroids with different optical and radar observation histories in order to ascertain the degree to which near-earth asteroid ephemerides can be improved by means of radar observations. For any given set of optical and radar observations and their associated errors, the angular and earth-asteroid distance uncertainties are calculated as functions of time through 2001. The radar data furnished only a small absolute improvement in such cases as that of 1627 Ivar, where a long history of optical astrometric data exists, but dramatic reductions in ephemeris uncertainties are obtainable for asteroids having only short optical data histories.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 94; 189-200
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  • 6
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    The multichannel astrometric photometer and atmospheric limitations in the measurement of relative positions (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The operational Multichannel Astrometric Photometer (MAP) now in use in the Allegheny Observatory astrometric program is the culmination of a decade of design and development effort. A detailed description of the system and its related software is followed by analysis of data acquired in four stellar regions. The study indicates an accuracy (in the sense of conformity to the best model), per night, for stars of the eighth magnitude or brighter, of 0.003 arcsec or better. These data points each have approximately twice the precision of the annual normal points obtained in our photographic program. Accuracy is shown to depend on: (1) the photon-count rate of the target star (it follows that the number of photons from the reference frame is also in important factor), (2) the duration of the observation, (3) the angular size of the reference frame, and (4) the quality of the astronomical seeing. Since (4) and, to a lesser extent, (1) involve the atmospheric characteristics at the time of observation, the probable performance at more favorable sites is discussed briefly.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 94; 213-224
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  • 7
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    GUST86 - An analytical ephemeris of the Uranian satellites (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The General Uranus Satellite Theory GUST (Laskar, 1986) is used for the construction of an analytical ephemeris for the Uranian satellites. The theory is fitted against earth-based observations from 1911 to 1986, and all radio and optical data obtained during Voyager encounter with Uranus. Earth-based observations alone allow the determination of masses which are within 15 percent of the values determined by the Uranus flyby. The analysis of all the observations confirm the values of the masses obtained during the encounter (Stone and Miner, 1986) and give a complete set of dynamical parameters for the analytical theory. An analytical ephemeris, GUST86, with an estimated precision of about 100 km with respect to Uranus is obtained.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics (ISSN 0004-6361); 188; 1, De
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  • 8
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    All-sky monitors for X-ray astronomy (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The rationale for a semipermanent all-sky X-ray monitor and a variety of options for its implementation are discussed. It is concluded that the Space Station offers an excellent opportunity for hosting such a monitor, and that a set of pinhole cameras can be configured to provide an effective and economical monitor system. A baseline of six independent pinhole modules, each of which requires approximately 1 cu ft, 30 pounds, 2 W and 100 bits per second, can provide full sky coverage with scientifically interesting sensitivities. No other resources or special accommodation (such as detailed alignment registration, time-tagging, or on-orbit servicing) would be required. The baseline system can locate bright sources to a few arcmin and can simultaneously measure each of the several hundred sources in the sky brighter than a few thousandths the intensity of the Crab nebula every day for decades.
    Keywords: ASTRONOMY
    Type: Space Science Reviews (ISSN 0038-6308); 45; 3-4,
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  • 9
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    The MIT spectroscopy investigations on AXAF and the study of supernova remnants (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The MIT High Resolution X-Ray Spectroscopy experiment on the AXAF, which will study physical conditions in celestial sources by means of detailed measurements of emission and absorption features in their spectra, involves two complementary dispersive instruments: Bragg Crystal Spectrometer (BCS) and High Energy Transmission Grating (HETG). This paper discusses the principles of operation of BCS and HETG and the results that will be obtained by these instruments. Measurements of individual line strengths obtained by the AXAF spectrometers will allow the application of plasma diagnostic techniques to a study of the detailed physical conditions in celestial objects, particularly in the optically thin plasma of supernova remnants, which is particularly well suited to the application of plasma diagnostics.
    Keywords: ASTRONOMY
    Type: Astrophysical Letters and Communications (ISSN 0888-6512); 26; 1-2,
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  • 10
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    The advanced X-ray astrophysics facility - An overview (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: This paper presents an overview of NASA's Advanced X-Ray Astrophysics Facility (AXAF), which is planned for launch in the 1990s and is expected to operate in space for at least 15 years. The design of the X-ray telescope is discussed and the instruments that may fly at the start of the AXAF mission, the principal investigator of each instrument, and the instrument performance parameters are listed. The AXAF instruments will include low-energy and high-energy transimission gratings, a Bragg crystal spectrometer, CCD imagers, an X-ray calorimeter, and a microchannel plate imager. The long lifetime of the AXAF will make it possible to follow up on the HEAO-2/Einstein results, the more recent X-ray observations performed by European and Japanese satellites, and the future ROSAT all-sky survey. The long lifetime of the AXAF, together with the servicing capability that will be offered by the Space Station, will also provide the opportunity of incorporating other instruments into the observatory.
    Keywords: ASTRONOMY
    Type: Astrophysical Letters and Communications (ISSN 0888-6512); 26; 1-2,
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  • 11
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    Plasma structures in comets P/Halley and Giacobini-Zinner (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: An overview of large-scale plasma phenomena is presented based on results of spacecraft probing of comets Halley and Giacobini-Zinner and on worldwide submissions to the Large-Scale Phenomena Discipline Specialist Team of the International Halley Watch. Examples of tail phenomena and science are presented with emphasis on observed disconnection events. The archive of this material will clearly be very valuable for studying the comet/solar-wind interaction during the 1985-1986 apparition of Halley's comet.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics (ISSN 0004-6361); 187; 1-2,
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  • 12
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    IRAS known asteroid prediction and association (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Techniques and procedures employed to obtain data concerning the known asteroids from IRAS observations are discussed. The IRAS observations covered 95 percent of the sky with at least four scans of the telescope field of view. A search was first carried out for geometrical intersections of the trajectories of a given asteroid and the telescope boresight, following which a matched sighting was sought for each such intersection among the actual IRAS point source detections. By using ground based measurements of visual magnitudes, IRAS observations of IR brightness, and a thermal model, albedos and diameters have been computed for 1,822 known asteroids, increasing the amount of this kind of information by about an order of magnitude.
    Keywords: ASTRONOMY
    Type: Journal of the Astronautical Sciences (ISSN 0021-9142); 35; 287-299
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  • 13
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    On the simple models for the interpretation of centimeter-wavelength radio observations of asteroids (1987)
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    Publication Date: 2011-08-19
    Description: The predictions of the two-layer models used to interpret radio spectra of the asteroids have been examined. It is clear that one must treat the models with caution as the physics is highly simplifed. Although the predictions are in accord with physical expectations, careful attention to the circumstances of the observations is essential. The lack of short-centimeter wavelength measurements of dielectric properties is especially vexing. Some simple improvements to the models based on studies of the lunar radio emission by Keihm and using radar measurements of asteroid surface characteristics by Ostro and colleagues are suggested. Even so, the calculation of a realistic continuum-emission spectrum for asteroidal bodies from 20 cm wavelength to 20 microns wavelength remains a formidable task.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific, Publications (ISSN 0004-6280); 99; 1009-101
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  • 14
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    Observation by Pioneer 7 of He(+) in the distant coma of Halley's comet (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Plasma analyzer data obtained by Pioneer 7 during its approach to about 12.1 million km from the nucleus of Comet P/Halley are presently interpreted as He(+) generated by charge exchange of the solar wind He(2+) with neutral cometary material. The maximum He(+) flux was detected several hours after the closest March 20, 1986 approach of the spacecraft, and is noted to be not only larger than expected, but also to exhibit large, discontinuous flux changes.
    Keywords: ASTRONOMY
    Type: Icarus (ISSN 0019-1035); 71; 192-197
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  • 15
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    The feasibility of periodicity searches in gamma-ray astronomy (1987)
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    Publication Date: 2011-08-19
    Description: It is presently noted that, in some cases, the usually infeasible conduct of searches in gamma-ray astronomy can be rendered feasible by means of a time-smoothing technique that yields only a moderate sensitivity loss. The total observing time is subdivided into a convenient number m of subintervals, and summing the values of H of each of the subintervals. This will reduce the number of independent frequency values by a factor m due to the shorter observing time.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics (ISSN 0004-6361); 175; 1-2,; 353
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  • 16
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    A Palomar Observatory Sky Survey atlas of selected molecular clouds (1987)
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    Publication Date: 2011-08-19
    Description: Forty-three cold, dense molecular clouds are digitized from the Palomar Observatory Sky Survey glass plates and presented with epoch 1950.0 equatorial coordinates. Regardless of the cloud's extent, the digitized area is limited to a 23 arcmin square on the sky with pixel size of about 1.3 arcsec. The optical maps presented herein are useful for comparing complementary molecular cloud maps from radio or infrared instruments and can be obtained in FITS format for use on astronomical image-processing systems.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal Supplement Series (ISSN 0067-0049); 64; 127-129
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  • 17
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    Orbits of the ten small satellites of Uranus (1987)
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    Publication Date: 2011-08-19
    Description: Orbital elements are presented for the ten small satellites discovered by Voyager 2 at Uranus. These ten new satellites, whose provisional IAU designations are 1985UI and 1986UI through 1986U9, lie for the most part in equatorial, circular orbits; the most notable exception is 1986U8, the outer epsilon-ring shepherd, whose eccentricity e = 0.0101. Unlike the Voyager discoveries at Saturn, which included two co-orbiting satellites and three librators, the ten small Uranian satellites all have quite different semimajor axes.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 93; 1268-127
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  • 18
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    IRAS surface brightness maps of reflection nebulae in the Pleiades (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Surface brightness maps at 12, 25, 60, and 100 microns were made of a 2.5 deg x 2.5 deg area of the reflection nebulae in the Pleiades by coadding IRAS scans of this region. Emission is seen surrounding 17 Tau, 20 Tau, 23 Tau, and 25 Tau in all four bands, coextensive with the visible reflection nebulosity, and extending as far as 30 arcminutes from the illuminating stars. The infrared energy distributions of the nebulae peak in the 100 micron band, but up to 40 percent of the total infrared power lies in the 12 and 25 micron bands. The brightness of the 12 and 25 micron emission and the absence of temperature gradients at these wavelengths are inconsistent with the predictions of equilibrium thermal emission models. The emission at these wavelengths appears to be the result of micron nonequilibrium emission from very small grains, or from molecules consisting of 10-100 carbon atoms, which have been excited by ultraviolet radiation from the illuminating stars.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 313; 853-858
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  • 19
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    The IHW island network (1987)
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    Publication Date: 2011-08-19
    Description: Early astronomical photography of comets at perihelion encouraged the establishment of an International Halley Watch (IHW) Team for regularly photographing the Comet. The February 1986 period was particularly troublesome due to the limitations of cometary visibility in the Southern Hemisphere. Schmidt cameras were placed on Tahiti, Easter Island, Faraday Station on the Antarctic Peninsula, Reunion Island and in South Africa. Blue- and red-filter B/W images were obtained every night and color prints were occasionally shot. Each night's images were examined before the next night's photography. Several interesting anecdotes are recounted from shipping, manning and operation of the telescopes.
    Keywords: ASTRONOMY
    Type: Sky and Telescope (ISSN 0037-6604); 73; 258-263
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  • 20
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    Techniques for the analysis of data from coded-mask X-ray telescopes (1987)
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    Publication Date: 2011-08-19
    Description: Several techniques useful in the analysis of data from coded-mask telescopes are presented. Methods of handling changes in the instrument pointing direction are reviewed and ways of using FFT techniques to do the deconvolution considered. Emphasis is on techniques for optimally-coded systems, but it is shown that the range of systems included in this class can be extended through the new concept of 'partial cycle averaging'.
    Keywords: ASTRONOMY
    Type: Astrophysics and Space Science (ISSN 0004-640X); 136; 2, Au; 337-349
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  • 21
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    X-ray intensity and spectral variations in the BL Lac sources H2155-304 and PKS0548-322 (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The results from the X-ray observations of two BL Lacertae objects, H2155-304 and PKS0548-322, are presented. The observations were carried out with the HEAO-1 A2 Low Energy Detectors, the High Resolution Imager, and the Monitor Proportional Counter aboard the Einstein Observatory. Correlated X-ray intensity variations of about 20 percent in the 0.15-3.5 keV energy band and about 40 percent in the 1.5-10 keV energy band are observed in H2155-304 over a period of about 8 hr. A factor of two change in the intensity of PKS0548-322 in the 3.5-10 keV energy interval is also detected over a time interval of 1 hr. Variations in the X-ray intensity over a timescale of months and the hardening of the spectrum with increasing intensity are seen in the HEAO-1 A2 data on H2155-304. The shortest observed timescale for the variability is used to derive an upper limit on the mass of the central accreting source in the two BL Lac objects studied here.
    Keywords: ASTRONOMY
    Type: Royal Astronomical Society, Monthly Notices (ISSN 0035-8711); 227; 525-534
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  • 22
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    Formation of the terrestrial planets (1980)
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    Publication Date: 2011-08-18
    Description: Two growth mechanisms are identified for the development of the terrestrial planets: (1) gravitational instability leading to a collapse, and (2) gravitational accumulation caused by two-body collisions and coherence. The presence of a dynamically-significant gas phase would not affect either mechanism. Theoretical expressions are presented for the production of giant gaseous protoplanets by gravitational instability within a central dust layer. Gravitational accumulation is discussed with reference to the accumulation of planetesimals from a gas-free circumsolar swarm of bodies. Numerical simulations are given for the early stages of accumulation. The Safronov steady-state velocity is considered, noting that the competition between mutual collisional damping and gravitational acceleration by the members of a solar swarm yields a steady-state velocity distribution where the mean velocity is comparable to the escape velocity of the largest body. A time scale for accumulation is postulated on the basis of the radial distribution of a swarm of non-accreting bodies of equal size. The simultaneous gas-free accumulation of several terrestrial planets is noted. Attention is also given to growth mechanisms in gas-rich interplanetary media.
    Keywords: ASTRONOMY
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  • 23
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    Is the remnant of SN 1006 Crablike (1980)
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    Publication Date: 2011-08-18
    Description: The solid-state spectrometer on the Einstein Observatory and the GSFC cosmic X-ray spectrometer on OSO 8 have observed the X-ray spectrum of SN 1006. The data can be well represented by a power-law model with alpha = 1.2, similar to the spectrum of the Crab Nebula. This is in contrast to the radio and X-ray maps of SN 1006 which show a shell structure more typical of SNR with thermal X-ray emission. The X-ray spectrum is suggestive of nonthermal synchrotron emission, raising the possibility that the remnant of SN 1006 contains a source of relativistic electrons.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 240
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  • 24
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    Radio observation of comet Meier /1978f/ in 18-cm OH lines (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Observations of 18-cm OH spectral lines in comet Meier (1978f) with the 1000-ft. Arecibo telescope show spatial resolution of the OH coma by the 2.9 arcmin beam (=3.7 x 10 to the 5th km). The data agree with predictions of the solar Fraunhofer spectrum-pumping theory of comet OH excitation. On the assumption that the OH parent molecule (e.g., H2O) has a Haser-model scale length of about 1.0 x 10 to the 5th km at heliocentric distance 1 AU, an OH scale length of less than 10 to the 6th km, and probably near 1.0 x 10 to the 5th km is derived. Assuming a recently calculated value of the OH lifetime and the solar radiative pumping model, the results indicate an OH production rate of 10 to the 29th Kayser at heliocentric distance 2 AU.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics; 85; 1-2,; Sept
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  • 25
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    Near infrared photographic sky survey - A field index (1980)
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    Publication Date: 2011-08-17
    Description: The book presents an index of previously cataloged objects located in the fields of the northern sky included in the Steward Observatory Near Infrared Photographic Sky Survey, which was intended to be used for identification purposes in an effort to locate extremely red objects. The objects included in the index were taken from 16 catalogs of bright nebulae, dark nebulae, infrared objects, reflection nebulae, supernova remnants and other objects, and appear with their corresponding field numbers, computed field center coordinates, object name and 1950 epoch equatorial coordinates, as well as supplementary descriptive information as available. An appendix is also provided in which the center coordinates of each field are listed.
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  • 26
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    SS 433 - Intensive 4 month light curves (1980)
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    Publication Date: 2011-08-17
    Description: Photometry covering 100 nights during 1979 July-November is reported, in an unfiltered band (effectively 5200-8000 A), in a V band, and with a few measures in B. Correlation with the 13 day period of Crampton, Cowley, and Hutchings is found in the form of a double-peaked light curve. A more tentative connection with the 164 day 'precession' period suggested by a broad light minimum near a critical phase in the long cycle is found.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 238
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  • 27
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    Near infrared photography with a vacuum-cold camera (1980)
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    Publication Date: 2011-08-17
    Description: Sensitized cooled plates have been obtained of the Orion nebula region and of Sh2-149 in the wavelength ranges 8000 A-9000 A and 9,000 A-11,000 A with a recently designed and constructed vacuum-cold camera. Sensitization procedures are described and the camera design is presented.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 92
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  • 28
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    Stability of planetary orbits in binary systems (1980)
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    Publication Date: 2011-08-17
    Description: The possible existence of stable orbits is investigated in binary systems using Hill's method. Analytical stability conditions are established for satellites, for inner planets and for outer planets, allowing arbitrary values for the mass-ratio of the binary.
    Keywords: ASTRONOMY
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  • 29
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    On the capture of the Moon (1980)
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    Publication Date: 2011-08-17
    Description: This paper studies the possibility of lunar capture depending on variations of the solar mass under certain well specified conditions and assumptions regarding the behaviour of the three-body dynamical system formed by the Sun, Earth and Moon. It is found that a large amount of decrease in the solar mass (approximately 37%) would be required to allow capture if the model of the planar restricted problem of three bodies is assumed, if the masses of the Earth and Moon did not change and if the angular momentum of the Sun-Earth system did not change. Such large mass-changes of the Sun can not be associated with radiation mass losses only with catastrophic events, such as stellar close approaches.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics; 21; Apr. 198
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  • 30
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    The time-of-flight system on the Goddard medium energy gamma-ray telescope (1980)
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    Publication Date: 2011-08-17
    Description: A scintillation counter time-of-flight system has been incorporated into the Goddard 50 cm by 50 cm spark chamber gamma-ray telescope. This system, utilizing constant fraction timing and particle position compensation, digitizes up to 10 ns time differences to six bit accuracy in less than 500 ns. Event selection decisions, discriminating against upward-moving particles, are made prior to spark chamber triggering. The performance of this system during a November 1978 balloon flight is discussed.
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  • 31
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    Ultraviolet, X-ray, and infrared observations of HDE 226868 equals Cygnus X-1 (1980)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: During April, May, and July of 1978, HDE 226868, the optical counterpart of Cygnus X-1, was repeatedly observed in the ultraviolet with the IUE satellite. Some X-ray and infrared observations have been made during the same period. The general shape of the spectrum is that expected from a late O supergiant. Strong absorption features are apparent in the ultraviolet, some of which have been identified. The equivalent widths of the most prominent lines appear to be modulated with the orbital phase. This modulation is discussed in terms of the ionization contours calculated by Hatchett and McCray, for a binary X-ray source in the stellar wind of the companion.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 242
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  • 32
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    The necessity of new dynamical theories of the planets (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: ASTRONOMY
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  • 33
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    The luminosity functions of the 1969 Perseid and Orionid meteor showers (1980)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Observations of the 1969 Perseid and Orionid meteor showers are presented and used to derive luminosity functions for the 288 Perseids and 56 Orionids detected. Visual counts were performed under very good to excellent seeing conditions at the times of peak activities, and the brightnesses of the meteors were estimated to the nearest magnitude by comparison with the magnitudes of known objects. Maximum likelihood estimates of the power law index of the luminosity function of 1.56 + or - 0.06 for the Perseids and of 1.85 + or - 0.1 for the Orionids are obtained which are lower than the values found by other investigators. Under the assumption that the luminosity of visual meteors is proportional to their mass, the luminosity function power law may also be used to characterize the mass function.
    Keywords: ASTRONOMY
    Type: Icarus; 43; Sept
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  • 34
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    On the detection of other planetary systems - Detection of intrinsic thermal radiation (1980)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: There is currently no unambiguous observational evidence for the existence of other planetary systems. One possible way to detect and study such systems is infrared observations of continuum blackbody radiation from planets revolving around other stars. It is shown that the effective temperature of large planets revolving around mid- to late-spectral-type main-sequences stars is set by energy sources internal to the planet rather than by equilibrium with the radiation field of the central star, making them easier to detect than had been previously thought. Consideration is given to the two major observational constraints on detecting planetary companions to nearby stars, namely, angular resolution and sensitivity. A comparison is made between the performance of an ambient (T 200 K), single-aperture telescope and a cooled interferometer. In each case the required aperture (baseline) is large (in the 10-m class), but consistent with Shuttle launch capability.
    Keywords: ASTRONOMY
    Type: Icarus; 43; Sept
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  • 35
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    Results from the 10 March 1977 occultation by the Uranus system (1980)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Timings of occultation events observed at Perth, Australia during the appulse of Uranus to SAO 158687 are presented. In addition to pre- and post-appulse observations of the alpha ring, a search of the data confirms events by the '4', '5', and '6' rings on the pre-appulse side of Venus, and the '5' and beta rings on the post-appulse side. A table of other suspected events obtained from a statistical search of the data down to the same level of significance as the '4', '5', and '6' events is presented. A fairly strong 'event', so far unconfirmed, is noted near the 5:1 Miranda resonance orbit. Examination of the light curves at high time resolution indicates that the alpha ring was, during this aspect, about 10 km in radial extent and about 50% transparent.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 85; Dec. 198
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  • 36
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    The hard X-ray pulse profile of GX 1+4 (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Results are reported from 1976 and 1977 observations of the galactic center X-ray source GX 1+4. On these two occasions, epoch folding at twice the previously reported period of about two minutes has resulted in an asymmetry between the shapes of the two resultant peaks in the light curve, indicating that the true period may be about four minutes. Mean intensity is shown to vary from pulse to pulse.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 240
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  • 37
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    The Space Telescope Observatory (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Space Telescope is an international astronomical observatory which will be placed into a low earth orbit in December 1983. The observatory will provide astronomers the opportunity to use five different instruments (wide field/planetary camera, faint object camera, high-resolution spectrograph, faint-object spectrograph, and high speed photometer), and to do astrometry with the use of the fine guidance sensors used primarily for pointing control. These instruments, the spectral range available above the earth's atmosphere, and the spatial resolution available from the combination of a near-diffraction limited 94-in. primary mirror and the stability provided by the Pointing Control System provide a tremendous potential to the astronomical community.
    Keywords: ASTRONOMY
    Type: Journal of the Astronautical Sciences; 28; Apr
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  • 38
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    Galileo's observations of Neptune (1980)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: Galileo's recorded observations of Neptune are examined, including an assessment of the accuracies of the positions of Neptune and those of the Jovian satellites. It is shown that one observation may be of astrometric value. The possible error in the ephemeris of Neptune is also discussed.
    Keywords: ASTRONOMY
    Type: Nature; 287; Sept. 25
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  • 39
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    A catalog of nonstellar water maser sources (1980)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: A list of 195 nonstellar galactic sources of water maser emission has been compiled. This list is not a comprehensive catalog of all the available information; it is intended to be used as an index. As such, it contains only coordinates, velocities, and selected references. The extragalatic sources are listed in a separate table.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 85; Sept
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  • 40
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    The observation, detection and research on satellites of asteroids (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Evidence is presented for the existence of asteroidal satellites. Instances wherein the occultation of a star occurred when a known asteroid was close to the line of sight of the star are discussed, and the implication that the eclipses were caused by satellites of the asteroids is considered. The role of amateur astronomers in these observations is reviewed, and possible applications of the technique of indirect occultation with regard to the solar system are discussed.
    Keywords: ASTRONOMY
    Type: L'Astronomie; 94; July-Aug
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  • 41
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    Effect of solar radiation on a swarm of meteoric particles (1980)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: The theory of the Poynting-Robertson effect is used to study the motion of meteors relative to a parent comet describing an undisturbed elliptical orbit. It is shown that any emitted particle proceeds to move retrogressively away from the comet to a certain maximum angular distance (as seen from the sun) depending on its sigma-s value, and then undergoes relative motion in the opposite forward direction. The time taken to reach this greatest elongation behind the comet is the same for all particles, and after twice this time the particles will have returned to zero angular displacement relative to the comet. For comet Encke the time for the elongation to return to zero is about 6600 y; for Halley it is about 200,000 y; for Temple-Tuttle (1965 IV) it is just over 100,000 y.
    Keywords: ASTRONOMY
    Type: Moon and the Planets; 23; Aug. 198
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  • 42
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    VLBI observations at 18 and 2.8 cm - 0133 + 47, 0735 + 178, OH 471, OQ 172, 1633 + 38, and NRAO 667 /2147 + 145/ (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 85; June 198
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  • 43
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    Molecular line observations of AFGL sources (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: HCN and (with three exceptions) CH emission lines have been detected from 14 molecular clouds associated with AFGL sources and/or Sharpless regions. Eleven are molecular cloud-H II region complexes. The remaining three appear to be similar (perhaps younger) objects; they are strong in the far infrared, but have no visible H II regions. Enhancement of the lower satellite transition of CH is seen in most cases. CH was also detected in association with the Herbig B8-A2e star V380 Ori. This emission was the most intense of all the CH detections. An effort was made to find a maser transition for a carbon-bearing molecule in late-type stars. A search was made for rotational transitions in the HCN bending mode (first overtone at 89.1 GHz) and stretching mode (fundamental at 88.0 GHz) as well as the CH ground state lambda-doublet in carbon stars.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 91
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  • 44
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    Infrared spectrometer for Voyager (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The Voyager IR investigation is described, which uses a Michelson interferometer in the 180-2500/cm range, and a single-channel radiometer for the visible and near-IR, sharing a 50-cm diameter telescope. Emphasis is placed on the differences between the Voyager and the previous designs, including reductions in the field of view and in the noise equivalent spectral radiance of the instrument. Attention is given to the optical layout, the electronics module, power supply placement, thermal control heaters and flash heaters, data reduction, and calibration. A sample spectrum of Jupiter is also discussed.
    Keywords: ASTRONOMY
    Type: Applied Optics; 19; May 1
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  • 45
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    Optical redshifts of 59 galaxies (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: This paper presents the results of an observing program carried out to measure galaxy redshifts with the Cassegrain Digicon Spectrograph system on the McDonald Observatory 2.1 m Struve telescope. New redshift determinations are presented for 59 galaxies, obtained for emission line spectra by conventional wavelength determination techniques and for absorption line spectra by Fourier transform filtering and cross correlation techniques with respect to velocity standard spectra of NGC 3115 and NGC 4736. With respect to published redshifts for 29 galaxies, the new redshifts show a mean residual of -1 km/sec and rms residual of 49 km/sec, without apparent systematic trends, from -300 to +13,700 km/sec.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 85; Feb. 198
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  • 46
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    Maintaining an expert system for the Hubble Space Telescope ground support (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The transformation portion of the Hubble Space Telescope (HST) Proposal Entry Processor System converts astronomer-oriented description of a scientific observing program into a detailed description of the parameters needed for planning and scheduling. The transformation system is one of a very few rulebased expert systems that has ever entered an operational phase. The day to day operations of the system and its rulebase are no longer the responsibility of the original developer. As a result, software engineering properties of the rulebased approach become more important. Maintenance issues associated with the coupling of rules within a rulebased system are discussed and a method is offered for partitioning a rulebase so that the amount of knowledge needed to modify the rulebase is minimized. This method is also used to develop a measure of the coupling strength of the rulebase.
    Keywords: ASTRONOMY
    Type: NASA, Goddard Space Flight Center, Proceedings of 1987 Goddard Conference on Space Applications of Artificial Intelligence (AI) and Robotics; p 1-1
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  • 47
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    Optical electronics for meteor observations (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Spectral observations of meteors have been carried out for several years using an optical electronics facility. Interest has centered on faint meteors and their trails in the period of intensive meteor showers. Over 800 meteors were registered during the observation period, with spectrograms obtained for 170 of these. A total of 86 meteors were photographed from two sites and for 25 of these spectrograms of the meteors as well as their trails were obtained. All meteors have undergone routine processing in order to determine atmospheric characteristics. Results are discussed.
    Keywords: ASTRONOMY
    Type: International Council of Scientific Unions, Middle Atmosphere Program. Handbook for MAP, Volume 25; p 410-415
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  • 48
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    Imaging interferometry with non-redundant arrays (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The performance of a set of nonredundant arrays, that convert an existing telescope to an interferometer, was simulated. Each array is a perforated mask, placed at an image of the objective. Each pair of holes in a mask transmits a unique spatial frequency that is present in the target; hence the term nonredundant. Each mask produces a fringe I(f) in the focal plane that is the product of the Fourier transforms of the object and the optical transfer function S(f).
    Keywords: ASTRONOMY
    Type: NASA-Goddard Space Flight Center, Theoretical Problems in High Resolution Solar Physics, 2; p 143-144
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  • 49
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    Spectroscopy and nonthermal processes (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Stellar spectra are analyzed to determine nonthermal processes for cool stars. A shock wave crossing model is supported by a study of the behavior of absorption and emission spectra. The shock waves are attributed to atmospheric kinetics. Circumstellar spectral lines are studied for information about gaseous circumstellar layers. The description of stellar envelopes is carried on through circumstellar dust. Characteristic properties of polarization in the dust are described in the case of specific stars, emphasizing narrowband observations in Mira, semiregular, and supergiant stars. Finally, the direct approach to measuring the angular diameters of stars and mapping the distribution of circumstellar dust and gas by lunar occultation or interferometry is discussed, using two prototype stars, an M supergiant and a dusty carbon star.
    Keywords: ASTRONOMY
    Type: NASA, Washington, The M-Type Stars; p 113-207
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  • 50
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    Ultraviolet spectral morphology of the O stars. IV - The OB supergiant sequence (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: An atlas of 25 O3-B8 supergiant spectra in the wavelength ranges 1320-1580 A and 1620-1880 A is presented, based on high-resolution data from the IUE archives. The remarkably detailed relationship between the stellar-wind profiles and the optical spectral classifications throughout this sequence is emphasized. For instance, the (Si IV)/(C IV) ratio reverses between O4 and O6.5; and the B0, B0.5, and B0.7 Ia wind characteristics are each qualitatively unique and distinct from one another. The systematic behavior of nine stellar-wind features with ionization potentials ranging from 114 to 19 eV is summarized as a function of advancing spectral type.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific, Publications (ISSN 0004-6280); 99; 40-53
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  • 51
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    Infrared-ultraviolet spectra of active galactic nuclei (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Data from IRAS and IUE were combined with ground based optical and infrared spectrophotometry to derive emission line free spectral energy distributions (SEDs) for 29 active galactic nuclei (AGNs) between 0.1 and 100 microns. The IRAS data were scaled down to account for extended emission. These correction factors, determined by comparing small aperture ground based 10.6 micron data with large aperture IRAS 12 micron fluxes, were usually less than 25%. These corrected SEDs are shown.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 727-729
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  • 52
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    Spectrophotometery of Brackett lines in very luminous IRAS galaxies (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Observation of the Brackett-alpha and Brackett-gamma hydrogen recombination lines were made in a sample of galaxies chosen from the IRAS catalog to have high luminosities at infrared wavelengths. Most have strong Brackett line emission indicating large numbers of high mass stars; the formation of these stars may hence be the underlying source for the galaxies' luminosities. However, there are at least two exceptions that may not be explained in this manner: NGC 6240 and Arp 220. Additional evidence indicates that each of these exceptions may be more closely related to Seyfert-type galaxies or other active galactic nuclei.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 701-705
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  • 53
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    A very deep IRAS survey at l(II) = 97 deg, b(II) = +30 deg (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A deep far-infrared survey is presented using over 1000 scans made of a 4 to 6 sq. deg. field at the north ecliptic pole by the IRAS. Point sources from this survey are up to 100 times fainter than the IRAS point source catalog at 12 and 25 micrometers, and up to 10 times fainter at 60 and 100 micrometers. The 12 and 25 micrometer maps are instrumental noise-limited, and the 60 and 100 micrometer maps are confusion noise-limited. The majority of the 12 micrometer point sources are stars within the Milky Way. The 25 micrometer sources are composed almost equally of stars and galaxies. About 80% of the 60 micrometer sources correspond to galaxies on Palomar Observatory Sky Survey (POSS) enlargements. The remaining 20% are probably galaxies below the POSS detection limit. The differential source counts are presented and compared with what is predicted by the Bahcall and Soneira Standard Galaxy Model using the B-V-12 micrometer colors of stars without circumstellar dust shells given by Waters, Cote and Aumann. The 60 micrometer source counts are inconsistent with those predicted for a uniformly distributed, nonevolving universe. The implications are briefly discussed.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 547-552
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  • 54
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    The initial mass function in HII galaxies (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Observation of a large sample of HII galaxies shows that the emission line ratios of the youngest objects change systematically with gaseous oxygen abundance, which was interpreted as resulting from changes in the initial mass function (IMF) of the ionizing cluster. Comparison with cluster/nebula models shows that both the slope and the upper mass limit of the cluster IMF vary with abundance. In HII galaxies with oxygen abundance about 1/10 that of Orion, the IMF for massive stars must have a slope which is about a factor of 2 smaller than in the Solar Neighborhood.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 479-482
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  • 55
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    Extragalactic infrared spectroscopy (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The spectra of galaxies in the near infrared atmospheric transmission windows are explored. Emission lines were detected due to molecular hydrogen, atomic hydrogen recombination lines, a line attributed to FEII, and a broad CO absorption feature. Lines due to H2 and FEII are especially strong in interacting and merging galaxies, but they were also detected in Seyferts and normal spirals. These lines appear to be shock excited. Multi-aperture measurements show that they emanate from regions as large as 15 kpc. It is argued that starbursts provide the most plausible and consistent model for the excitation of these lines, but the changes of relative line intensity of various species with aperture suggest that other excitation mechanisms are also operating in the outer regions of these galaxies.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 421-433
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  • 56
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    CO observations of galaxies with the Nobeyama 45-M telescope (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: High-resolution (15 inch), filled aperture maps of the CO (J = 1-0) line emission were obtained for several nearby, CO-bright galaxies like M82, M83, IC342, and NGC891 in order to study star forming activity in these galaxies.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 179-196
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  • 57
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    A correlation between the IRAS infrared cirrus at 60 or 100 microns and neutral atomic hydrogen in the outer galaxy (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A linear correlation was found between the infrared cirrus at 100 or 60 microns and neutral atomic hydrogen near the galactic plane. Infrared Astronomy Satellite (IRAS) Sky Brightness images were compared to the 0.5 deg resolution Weaver-Williams HI survey in two regions of the outer Galaxy near l = 125 deg and l = 215 deg. The dust temperature inferred is nearly uniform and in reasonable agreement with theoretical predictions of thermal dust emission.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 103-105
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  • 58
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    The Arp Ring: Galactic or extragalactic? (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The Arp Ring is a faint, loop-like structure around the northern end of M81 which becomes apparent only on deep optical photographs of the galaxy. The nature of the Ring and its proximity to M81 are uncertain. Is it simply foreground structure, part of this galaxy, or is it within the M81 system? Infrared Astronomy Satellite (IRAS) maps of the region show a far-infrared counterpart of the Ring. The infrared data are compared with previous optical and radio observations to try to ascertain its physical nature. The poor correlation found between the common infrared/optical structure and the distribution of extragalactic neutral hydrogen, and the fact that its infrared properties are indistinguishable from those of nearby galactic cirrus, imply that the Arp Ring is simply a ring structure in the galactic cirrus.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 107-110
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  • 59
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    Erratum: IRAS observations of irregular galaxies (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: In Infrared Astronomy Satellite (IRAS) observations of irregular galaxies, galactic blue luminosities were based on standard optical definitions. The blue luminosities (L sub B) were derived from the blue absolute magnitude (M sub B) or form the in band flux. However, the L sub B system for spiral galaxies was based on quasi-bolometric (rather than in band) fluxes. The formulation and resulting statements are corrected.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 257
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  • 60
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    IRAS observations of irregular galaxies (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Normal irregular galaxies seem to be unusual in having vigorous star formation yet lacking the many dark nebulae typical of spirals. The Infrared Astronomy Satellite (IRAS) observations of a large sample of irregulars are used to explore the dust contents of these galaxies. Compared to normal spirals, the irregulars generally have higher L sub IR/L sub B ratios, warmer f(100)/f(60) dust color temperatures, and lower globally-averaged dust/gas ratios. The relationship between the infrared data and various global optical properties of the galaxies is discussed.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 253-256
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  • 61
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    Stellar bars and the spatial distribution of infrared luminosity (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Ground-based 10 micron observations of the central region of over 100 infrared luminous galaxies are presented. A first order estimate of the spatial distribution of infrared emission in galaxies is obtained through a combination of ground-based and Infrared Astronomy Satellite (IRAS) data. The galaxies are nearby and primarily noninteracting, permitting an unbiased investigation of correlations with Hubble type. Approximately 40% of the early-type barred galaxies in this sample are associated with enhanced luminosity in the central (approximately 1 kpc diameter) region. The underlying luminosity source is attributed to both Seyfert and star formation activity. Late-type spirals are different in that the spatial distribution of infrared emission and the infrared luminoisty are not strongly dependent on barred morphology.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 219-226
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  • 62
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    IRAS observations of the Pleiades (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The Infrared Astronomy Satellite (IRAS) observations of the Pleiades region are reported. The data show large flux densities at 12 and 25 microns, extended over the optical nebulosity. This strong excess emission, implying temperatures of a few hundred degrees Kelvin, indicates a population of very small grains in the Pleiades. It is suggested that these grains are similar to the small grains needed to explain the surface brightness measurements made in the ultraviolet.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 117-121
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  • 63
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    Infrared properties of dust grains derived from IRAS observations (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The analysis of several diffuse interstellar clouds observed by the Infrared Astronomy Satellite (IRAS) is presented. The 60/100 micron flux ratios appear to be nearly constant in clouds with up to 1 sup m visual extinction at the center. Observations of a highly regular cloud in Chamaeleon show that the 12/100 micron ratio peaks at an intermediate radial distance and declines towards the center of the cloud. These observations indicate that nonequilibrium emission accounts only for the 12 and 25 micron bands; strong emission observed at the 60 micron band is probably due to equilibrium thermal radiation. The correlation of the 12 micron emission with a red excess observed for a high latitude cloud, L1780, is shown to be consistent with the assumption that both features are due to fluorescence by the same molecular species.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 113-116
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  • 64
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    On the redistribution of OB star luminosity and the warming of nearby molecular clouds (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Infrared Astronomy Satellite (IRAS) observations of the neighborhoods of six outer-Galaxy HII regions were combined with CO observations to show that most of the far infrared (FIR) luminosity from within approximately 25 to 75 pc of the ionizing stars is contributed by dust in molecular clouds, not by dust in the low-density ionized gas. Dust associated with the clouds is warmed by absorption of UV and visible light from the cluster of stars responsible for the ionization. Most of the OB cluster starlight is not absorbed locally. A fraction of the order of 10% of the OB cluster luminosity is absorbed by nearby molecular clouds and reradiated as FIR light. The luminosity per unit mass for the heated clouds is approximately 3 to 13 solar luminosity/solar mass, approximately one order of magnitude greater than the corresponding ratio for clouds found near clusters without O stars, and two orders of magnitude greater than the ratio for dark clouds heated primarily by the interstellar radiation field. If the observations of clouds near outer-Galaxy HII regions are used to characterize the molecular clouds heated by HII regions in the inner-Galaxy, then at most 30% of the Galaxy's molecular cloud mass is actively engaged in the formation of massive stars at the present time.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 75-78
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  • 65
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    High energy gamma ray astronomy (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: High energy gamma ray astronomy has evolved with the space age. Nonexistent twenty-five years ago, there is now a general sketch of the gamma ray sky which should develop into a detailed picture with the results expected to be forthcoming over the next decade. The galactic plane is the dominant feature of the gamma ray sky, the longitude and latitude distribution being generally correlated with galactic structural features including the spiral arms. Two molecular clouds were already seen. Two of the three strongest gamma ray sources are pulsars. The highly variable X-ray source Cygnus X-3 was seen at one time, but not another in the 100 MeV region, and it was also observed at very high energies. Beyond the Milky Way Galaxy, there is seen a diffuse radiation, whose origin remains uncertain, as well as at least one quasar, 3C 273. Looking to the future, the satellite opportunities for high energy gamma ray astronomy in the near term are the GAMMA-I planned to be launched in late 1987 and the Gamma Ray Observatory, scheduled for launch in 1990. The Gamma Ray Observatory will carry a total of four instruments covering the entire energy range from 30,000 eV to 3 x 10 to the 10th eV with over an order of magnitude increase in sensitivity relative to previous satellite instruments.
    Keywords: ASTRONOMY
    Type: Essays in Space Science; p 227-274
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  • 66
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    Space Infrared Telescope Facility (SIRTF) design and thermal analysis (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The design and performance characteristics of an observatory are compared with those of a storage dewar. The critical design technologies required to increase cryogen dewar lifetime are discussed. In particular, outer shell temperature, vapor cooled shields, multilayer insulation performance, and tank support systems are analyzed to assess their impact on cryogen lifetime for both the observatory and the storage dewar. The cryogen lifetime and cryogen mass loss rate of the Space Infrared Telescope Facility (SIRTF) are compared with that of the Infrared Astronomy Satellite and the Cosmic Background Explorer Satellite. A 0.1 percent mass loss per day of superfluid helium dewar can be designed using current state-of-the-art dewar technology. Space-based liquid hydrogen and liquid oxygen tanks can be designed for a 5-year lifetime.
    Keywords: ASTRONOMY
    Type: NASA. Lewis Research Center, Cleveland, Ohio. Cryogenic Fluid Management Technology Workshop. Volume 1: Presentation Material and Discussion; p 193-220
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  • 67
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    The radio-far infrared correlation: Spiral and blue compact dwarf galaxies opposed (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The recently established correlation between radio continuum and far infrared emission in galaxies was further investigated by comparing normal spiral and blue compact dwarf galaxies. The puzzling result is that the ratio of radio to far infrared luminosity and its dispersion is the same for both samples, although their ratios of blue to far infrared luminosity, their radio spectral indices and their dust temperatures exhibit markedly different mean values and dispersions. This suggests that the amount of energy radiated in the two regimes is enhanced in the same way although the mechanisms responsible for the two components are rather different and complex. The fact that the blue light does not increase at the same proportion shows that both the radio and the far infrared emission are connected with the recent star formation history.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 583-588
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  • 68
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    Radio and infrared observations of (almost) one hundred non-Seyfert Markarian galaxies (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The 13 cm flux densities of 96 non-Seyfert Markarian galaxies were measured at Arecibo Observatory. Far infrared flux densities have been published for 78 of these galaxies in the IRAS catalog. The radio, infrared, and optical fluxes of these galaxies and of a magnitude limited sample of normal galaxies were compared to clarify the nature of the radio emission in Markarian galaxies. It was found that Markarian galaxies of a given apparent magnitude and Hubble type generally have radio fluxes several times higher that the fluxes typical of normal galaxies of the same magnitude and type. Remarkably, the ratio of radio flux to far infrared flux is nearly the same for most of these starburst galaxies and for normal spiral disks. However, the compact and peculiar Markarian galaxies consistently have about 60% more radio flux per unit infrared flux than the other Markarian galaxies and the normal spirals. It is not clear whether this difference reflects a difference in the evolution of the starbursts in these galaxies or whether there is excess radio emission of nonstellar origin.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 579-582
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  • 69
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    The infrared morphology of galactic centers (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: Initial results are presented of a program to map the centers of galaxies in the mid-infrared using the NASA-MSFC 20 pixel bolometer array. Maps at 10.8 micrometer of the galaxies NGC 5236 (M82), NGC 1808, NGC 4536, and NGC 4527 reveal complex emitting regions ranging in size from 500 pc to 2 kpc. The infrared spatial distributions generally resemble those in the visible and radio. In all cases a large fraction of the IRAS 12 micrometer flux originates in spatial structures prominent in the maps.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 497-500
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  • 70
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    The azimuthal and radial distributions of HI and H2 in NGC 6946 (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: A study was completed of the atomic and molecular components of the ISM in NGC 6946. The distribution of molecular clouds was determined from a fully sampled CO map of the inner disk using the 14-meter telescope of the FCRAO. The distribution of atomic gas was derived from VLA observations at 40" resolution in the D configuration. When comparing the global CO and HI properties with other components of the galaxy, it was found that the azimuthally averaged radial distributions of CO, H-alpha, radio continuum and blue light all exhibit similar roughly exponential falloffs, while the azimuthally averaged HI surface densities vary by only a factor of 2 out to R = 16 kpc. This indicates that while the H-alpha/CO ratio is approximately constant with radius, the CO/HI ratio decreases by a factor of 30 from the center of the galaxy to R = 10 kpc.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 491-495
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  • 71
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    VLA continuum observations of barred spiral galaxies (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Observations of NGC 613, NGC 1300, NGC 4314 and NGC 5383 using the VLA at frequencies of 1464.9 and 4885.1 MHz are reported. These objects are a subset of galaxies from which radio emission were searched. The selection criteria were: (1) they are barred spiral galaxies preferentially with different Hubble type; (2) they have a peculiar or hot spot nucleus; (3) they have been observed at far infrared wavelengths by IRAS; and (4) they are observable from the northern hemisphere. Their radio and far infrared properties are summarized and their composite spectra are shown.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 483-484
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  • 72
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    IRAS observations of starburst galaxies (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Far infrared properties of Starburst galaxies were analyzed using IRAS observations at 25, 60, and 100 micrometers. Seventy-nine of 102 Starburst galaxies from the list of Balzano were detected. These galaxies have high IR luminosities of up to a few 10 to the 12th power L sub 0 and concentrate in a small area of the IR color - color diagram. The IR power law spectral indices, alpha, lie within the ranges -2.5 〈alpha(60,25)〈 -1.5 and -1.5 〈alpha(100,60)〈 0. These observed indices can be interpreted in terms of a cold disk component and a warm component. More than 80% of the 60 micrometer emission comes from the warm component. The fraction of the 60 micrometer emission attributable to the warm component can be used as an activity indicator.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 507-511
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  • 73
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    Ultraluminous infrared galaxies (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: The IRAS survey of the local universe has revealed the existence of a class of ultraluminous infrared galaxies with L(8 to 1000 micrometer) greater than 10 to the 12th L sub 0 that are slightly more numerous, and as luminous as optically selected quasars at similar redshift. Optical CCD images of these infrared galaxies show that nearly all are advanced mergers. Millimeter wave CO observations indicate that these interacting systems are extremely rich in molecular gas with total H2 masses 1 to 3 x 10 to the 10th power M sub 0. Nearly all of the ultraluminous infrared galaxies show some evidence in their optical spectra for nonthermal nuclear activity. It is proposed that their infrared luminosity is powered by an embedded active nucleus and a nuclear starburst both of which are fueled by the tremendous reservoir of molecular gas. Once these merger nuclei shed their obscuring dust, allowing the AGN to visually dominate the decaying starburst, they become the optically selected quasars.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 411-420
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  • 74
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    Modelling the IRAS colors of galaxies (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: A physical interpretation is proposed for the color-color diagram of galaxies which are powered only by star formation. The colors of each galaxy result from the combination of two components: cirrus-like emission from the neutral disk, and warmer emission from regions directly involved in on-going star formation. This approach to modelling the emission is based on dust properties, but independent evidence for it is found in the relation between the color sequence and the luminosity sequence. Implications of data and interpretations are discussed and possible tests mentioned for the model.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 319-322
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  • 75
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    IRAS colors of VLA identified objects in the galaxy (1987)
    In:  CASI
    Details
    Publication Date: 2013-08-31
    Description: Infrared Astronomy Satellite (IRAS) sources found within 4 degrees of l = 125 deg, b = 2 deg on the 3rd HCON 60 micron Sky Brightness Images were observed at the Very Large Array (VLA). Regions were to be identified where massive stars are forming by looking for small areas of radio continuum emissions. The IRAS sources could be divided into three groups by their IRAS 12 micron/25 micron and 60 micron/100 micron color. The group identified with star forming regions contained essentially all of the objects with extended radio emission. In all of these cases the extended radio emission showed a morphology consistent with the identification of these objects as HII regions. The conclusion drawn is that star formation regions can be distinguished from other objects by their infrared colors.
    Keywords: ASTRONOMY
    Type: NASA, Washington Star Formation in Galaxies; p 63-66
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  • 76
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    Infrared astronomy (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The role and contributions of Frank McDonald in extending high energy astrophysics to the sub-eV photon energy range (in putting infrared astronomy into orbit) are discussed.
    Keywords: ASTRONOMY
    Type: Essays in Space Science; p 395-401
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  • 77
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    X-ray astronomical spectroscopy (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The contributions of the Goddard group to the history of X-ray astronomy are numerous and varied. One role that the group has continued to play involves the pursuit of techniques for the measurement and interpretation of the X-ray spectra of cosmic sources. The latest development is the selection of the X-ray microcalorimeter for the Advanced X-ray Astrophysics Facility (AXAF) study payload. This technology is likely to revolutionize the study of cosmic X-ray spectra.
    Keywords: ASTRONOMY
    Type: Essays in Space Science; p 379-394
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  • 78
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    Hubble Space Telescope (1987)
    In:  CASI
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    Publication Date: 2013-08-31
    Description: The Hubble Space Telescope will employ magnetic torque controllers, which make use of the Earth's magnetic field augmented by four reaction wheels. DC torques are easily allowed for, but variations, orbit by orbit, can result in excessive wheel speeds which can excite vibratory modes in the telescope structure. If the angular momentum from aerodynamic sources exceeds its allocation of 100 Nms, the excess has to come out of the maneuvering budget since the total capacity of the momentum storage system is fixed at 500 Nms. This would mean that maneuvers could not be made as quickly, and this would reduce the amount of science return. In summary, there is a definite need for a model that accurately portrays short term (within orbit) variations in density for use in angular momentum management analyses. It would be desirable to have a simplified model that could be used for planning purposes; perhaps applicable only over a limited altitude range (400 to 700 km) and limited latitude band.
    Keywords: ASTRONOMY
    Type: Upper and Middle Atmospheric Density Modeling Requirements for Spacecraft Design and Operations; p 73-87
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  • 79
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    Central configurations and hyperbolic-elliptic motion in the three-body problem (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A refined classification of motion for the planar three-body problem with zero-sum total energy is presented. The structure and dimensions of the sets of initial conditions leading to parabolic expansion or hyperbolic-elliptic motion are found. Attention is given to the use of the Hamiltonian of the system and to the two- and three-dimensional problem. It is verified that the new coordinates of position and linear momentum approaches limits as t (time) approaches infinity, and that these limits constitute equilibrium solutions to the three-body problem representing control configurations.
    Keywords: ASTRONOMY
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  • 80
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    On the apparent secular accelerations of the moon and the sun (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The discussion of tidal friction in the earth-moon system given in successive editions of 'The Earth' by Jeffreys is shown to contain a serious dynamical error. When the treatment is corrected, it shows that the moment of inertia of the earth must be changing. The apparent secular accelerations of the moon and sun require a diminishing moment of inertia, and the rate is in agreement with the phase-change hypothesis for the nature of the core.
    Keywords: ASTRONOMY
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  • 81
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    Tidal-friction theory of the earth-moon system (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Serious errors contained in Jeffreys' (1952, 1959, 1970, 1976) discussion of tidal friction in the earth-moon system are identified and their consequences are discussed. A direct solution of the dynamical tidal equations for the couple from the earth acting upon the moon and the couple from the earth acting upon the sun, which were left unsolved by Jeffreys, is found to be incompatible with observations and the predictions of linear or quadratic friction theory, due to his failure to take into account the possible change of the moment of inertia of the earth with time in the derivation of the dynamical equations. Consideration of this factor leads to the conclusion that the earth must be contracting at a rate of 14.7 x 10 to the -11th/year, which can be accounted for only by the Ramsey theory, in which the terrestrial core is considered as a phase change rather than a change in chemical composition. Implications of this value for the rates of changes in day length and lunar distance are also indicated.
    Keywords: ASTRONOMY
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  • 82
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    IUE observations of two late type stars - R Aql and W Hya (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics; 92; 3, De; Dec. 198
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  • 83
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    On the rapid variability of AM Herculis (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: New observations of the rapid brightness flickering of AM Her are presented, with 10 hours of data from three nights and with a time resolution of 1.6 s, and the statistical properties of the flickering are described. The flickering is assumed to be the superposition of bursts produced as individual clumps in the accretion flow encounter the region of strong emission just above the surface of the white dwarf at the magnetic poles. A statistical shot-noise analysis is then appropriate, and a pulse duration of 70-90 s is determined, with many pulses overlapping at any instant. The clumps must then have the form of long, thin strings as they reach the emission region.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 241
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  • 84
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    X-ray astronomical spectroscopy (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The elementary spectral signatures of fundamental physical processes that might be operable in galactic and extragalactic X-ray sources are reviewed. Some of the instrument limitations of experimental techniques used in X-ray astronomical spectroscopy are described. X-ray spectroscopic measurements are examined for various types of X-ray-emitting objects, including degenerate and nondegenerate stellar systems, supernova remnants, clusters of galaxies, active galactic nuclei, and quasars.
    Keywords: ASTRONOMY
    Type: Vistas in Astronomy; 24; pt. 3
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  • 85
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    Graphical measurement of Saturn's oblateness and the radius of the Encke gap (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The geometric distortions attendant to spin-scan imaging were extraordinarily manifest in the Pioneer encounter with Saturn. By overlapping graphical predictions of these distortions with raster scans of the raw intensity data, both displayed to the same scale on a Versatec printer-plotter, it is possible to determine the precise geometry of a data-taking sequence. The predictions are quite sensitive to the assumed dimensions of Saturn and its rings. It is accordingly concluded that the ratio of polar to equatorial radius is 0.91 and that the Encke gap is 133,500 km from Saturn's center.
    Keywords: ASTRONOMY
    Type: Journal of Geophysical Research; 85; Nov. 1
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  • 86
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    A photometric study of the eclipsing binary RX Hercules (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A new photoelectric light curve of RX Hercules, a binary system with similar components, has been analyzed using Wood's computer model. RX Her, using Popper's spectroscopic mass ratio of q = 0.8472, turned out to be composed of a dimmer AO component and a larger B9.5 component. This detached system, upon analysis of the residuals in secondary minimum, shows some asymmetry during ingress which then disappears just before secondary minimum. The eccentricity e = 0.022 determined in this study is a little larger than previously published values of e = 0.018. In combination with the spectroscopic analysis of Popper, and ubvy data of Olson and Hill and Hilditch new photometric elements for RX Her were found.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics Supplement Series; 42; Dec. 198
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  • 87
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    Radio survey of Markarian galaxies at 6 and 11 cm (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: One hundred and fifty-one objects from Markarian's lists 6 and 7 were observed at 6 cm with a 3 sigma detection limit of about 30 mJy. Eight Markarian objects were detected, six of which were also observed at 11 cm. Forty-five others were negative at this wavelength. Two of the detections, numbers 533 and 668, are Seyfert galaxies; additionally, UB1 was detected at 6 cm and NGC 7715 and III Zw 2 were found at 11 cm.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 85; Nov. 198
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  • 88
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    Ultraviolet spectroscopy of comets (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The UV spectra of a comet, Comet Seargent 1978m, were obtained two weeks after the comet's discovery before any ground-based spectroscopic observations were made. The second comet observed with IUE was Comet Bradfield 1979e. It was first observed on January 10 and 11, 1980, and subsequently on several occasions until the beginning of March of 1980. The comets were observed at various heliocentric distances in the low and high dispersion mode. In the long wavelength region, emission bands of OH, CS, CO2(+), NH and CO(+) were identified, and the rotational structures of the (0, 0) and (1, 0) bands of OH were resolved. In the short wavelength region, emission lines of H(L alpha), O I, C I, C II, and C 1 and the CO fourth positive bands appeared. The results of these observations are the detection of S I; indications that CS exists as "Parent Molecules" in the cometary ice; the resolution of the (0, 0) and (1, 0) bands of OH; the determination of the spatial variations of various emissions; the determination of the variation of the production rates of various species, especially of H and OH, with heliocentric distance.
    Keywords: ASTRONOMY
    Type: ESA 2nd European IUE Conf.; 12 p
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  • 89
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    Potential in the central bar structure (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The figure-eight orbits obtained by Miller and Smith (1979) inside the central bar structure of galaxies are used to establish possible potential functions which result in such orbits. It is shown that r to the -6th power type potentials are special cases of distance and angle-dependent potential functions.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 239
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  • 90
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    Photometry of Southern Hemisphere red dwarf stars (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Results are presented for a photometric investigation of a spectroscopically selected sample of red dwarf stars in the Southern Hemisphere. Absolute magnitudes and distances for the stars are estimated from broadband red colors. Three stars which may be subluminous are identified, as are several stars which may be within 25 pc. The tangential velocity and velocity dispersion of the sample are similar to values found in other studies of nearby late-type stars.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 85; June 198
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  • 91
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    Absolute brightness temperature measurements at 3.5-mm wavelength (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Careful observations have been made at 86.1 GHz to derive the absolute brightness temperatures of the sun (7914 + or - 192 K), Venus (357.5 + or - 13.1 K), Jupiter (179.4 + or - 4.7 K), and Saturn (153.4 + or - 4.8 K) with a standard error of about three percent. This is a significant improvement in accuracy over previous results at millimeter wavelengths. A stable transmitter and novel superheterodyne receiver were constructed and used to determine the effective collecting area of the Millimeter Wave Observatory (MWO) 4.9-m antenna relative to a previously calibrated standard gain horn. The thermal scale was set by calibrating the radiometer with carefully constructed and tested hot and cold loads. The brightness temperatures may be used to establish an absolute calibration scale and to determine the antenna aperture and beam efficiencies of other radio telescopes at 3.5-mm wavelength.
    Keywords: ASTRONOMY
    Type: IEEE Transactions on Antennas and Propagation; AP-28; May 1980
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  • 92
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    IUE observations of circumstellar emission from the late type variable R Aquarii /M7 + pec/ (1980)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: IUE observations of R Aquarii (M7 + pec) have been obtained in low dispersion in order to study its circumstellar emission. Strong permitted, semiforbidden, and forbidden emission lines are identified that are superposed on a bright ultraviolet continuum. From the analysis it is deduced that the strong emission-line spectrum that involves semiforbidden C III, C IV, semiforbidden Si III, forbidden O II, and forbidden O III probably arises from a dense compact nebula the size of which is comparable to the binary system of which R Aqr is the primary star. Low-excitation emission lines of Fe II, Mg II, O I, and Si II suggest the presence of a warm chromosphere (T less than about 10,000 K) in the primary M7 late type giant. The secondary is identified as a white dwarf, comparable to or somewhat brighter than the sun, since such a star can produce enough ionizing photons to excite the continuum and emission-line spectrum and yet be sufficiently faint to escape detection by direct observation. The UV continuum observed is attributed to Balmer recombination and not to blackbody emission from the hot companion. The general spectral properties of R Aqr between 1200 A and 3200 A are discussed in the context of the model for the circumstellar nebula, the companion, and the mass-loss rate of the primary star.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 237
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  • 93
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    Rocket-ultraviolet imagery of the North America nebula (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: New ultraviolet imagery of NGC 7000 has been obtained in a sounding-rocket flight with an electrographic Schmidt camera which covers the 1230-2000 A wavelength range and has a higher angular resolution than the Apollo 16 imagery. The integrated brightness of NGC 7000 near 1450 A is unexpectedly high (three times the brightness of HD 199579 as measured by CHB), but as no emission lines were observed with a nebular spectrograph, it is concluded that the radiation observed in the UV image is nearly pure continuum. Comparison with the blue continuum image is not possible, as the latter image has dominant contributions due to night sky background, hydrogen recombination continuum, and possibly unresolved faint stars. It is suggested that the high UV brightness of NGC 7000 is due to the highly efficient dust scattering of stellar radiation.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 237
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  • 94
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    Cataloged infrared sources in NIPSS data. I - The RSO 1 catalog (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A small number of selected near-infrared and visual photographic pairs from the Steward Observatory Near Infrared Photographic Sky Survey have been examined for content of stars more red than (V-I) of about 2.5 magnitudes. A simple manual extraction of these objects was carried out as a part of a preliminary evaluation of survey data and techniques for reducing it; the resulting list has been compiled as the first installment of a Catalog of Red Stellar Objects (Craine et al. 1979). Results of a cross correlation of this catalog with the IRC, AFGL, and EIC infrared catalogs are here presented. The results indicate that these photographs may be particularly useful for purposes of optical identification of short-wavelength infrared sources to limits much fainter than represented by presently existing infrared catalogs.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 92
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  • 95
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    The perplexing spectrum of AFGL 2789 /V645 CYGNI/ (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Visual spectra and photometry from 0.35 to 18 microns show that AFGL 2789 may be one of the most interesting of the infrared sources now identified with reflection nebulae. It has an Ae-type shell spectrum with strong emission lines of hydrogen, Fe II, Cr II, and Ti II, but the most remarkable feature is a broad absorption band near 5500 A, presumably molecular, with three possible band heads. This absorption band was present on only one of two spectra taken one night apart. The two known molecules with wavelengths closest to the observed band heads are C2 and H2O(+), although there are problems with either of these as possible identifications.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 237
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  • 96
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    The space telescope scientific instruments (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper describes the space telescope with a 2.4 m aperture to be launched at 500 km altitude in late 1983. Four axial-bay and one radial-bay scientific instrument, a wide-field and planetary camera, a faint-object camera, a faint-object spectrograph, and a high-speed photometer are to be installed to conduct the initial observations. The axial instruments are constrained to envelopes with dimensions 0.9 x 0.9 x 2.2 m and their masses cannot exceed 317 kg. The observatory will also be equipped with fine-guidance sensors and a microprocessor. The design concepts of the instruments are outlined and some of the astronomical capabilities including studies of distant and local galaxies, physical properties of quasars, interrelations between quasars and active galactic nuclei are mentioned.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 92
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  • 97
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    Planetary radar astronomy (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The scientific aims, theoretical principles, techniques and instrumentation, and future potential of radar observations of solar-system objects are discussed in a general overview. Topics examined include the history of radar technology, echo detectability, the Arecibo and Goldstone radar observatories, echo time delay and Doppler shift, radar waveforms, albedo and polarization ratio, measurement of dynamical properties, and the dispersion of echo power. Consideration is given to angular scattering laws; the radar signatures of the moon and inner planets, Mars, and asteroids; topographic relief; delay-Doppler radar maps and their physical interpretation; and radar observations of the icy Galilean satellites of Jupiter, comets, and the rings of Saturn. Diagrams, drawings, photographs, and sample maps and images are provided.
    Keywords: ASTRONOMY
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  • 98
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    An atlas of optical spectrophotometry of Wolf-Rayet carbon and oxygen stars (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The atlas contains a homogeneous set of optical spectrophotometric observations (3300-7300 A) at moderate resolution (about 10 A) of almost all WC and WO stars in the Galaxy, the LMC, and the SMC. The data are presented in the form of spectral tracings (in magnitude units) arranged by subtype, with no correction for interstellar reddening. A montage of prototype stars of each spectral class is also shown. Comprehensive line identifications are given for the optical lines of WC and WO spectra, with major contributions tabulated and unidentified lines noted.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal Supplement Series (ISSN 0067-0049); 65; 459-483
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  • 99
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    Comments about observing conditions for UV astronomy aboard Spacelab (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The Spacelab missions provided a good opportunity for a first general UV survey of astrophysical objects. The UV observations carried out on Spacelab 1 yielded some new results, but revealed at the same time observing and operation constraints which must be considered for planning and preparing for future Spacelab experiments. Experience gained with two astronomical experiments, the UV Very Wide Field Camera (1ES022) and FAUST Far Ultraviolet Telescope (1NS-005) are discussed.
    Keywords: ASTRONOMY
    Type: Advances in Space Research (ISSN 0273-1177); 7; 5, 19
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  • 100
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    VLBI observations of the 3C 111 jet (1987)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: VLBI observations have been made of the central component of the broad-line radio galaxy 3C 111 at 1.7 GHz and 5.0 GHz. High-dynamic-range maps at both frequencies show a one-sided jet in PA 62 + or - 1 deg but no counterjet. The lower limit to the jet/counterjet ratio is 30:1 at 5 GHz and 15:1 at 1.7 GHz. The jet is initially straight, but beyond 15 marcsec from the core it exhibits small bends or wiggles. Their onset corresponds to a sharp reduction in the rate of intensity falloff along the jet, suggesting that an instability in the jet is causing substantial particle acceleration.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 317; 121-127
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