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  • ASTROPHYSICS  (709)
  • ASTRONOMY
  • 1985-1989  (927)
  • 1980-1984
  • 1975-1979
  • 1985  (927)
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  • 1985-1989  (927)
  • 1980-1984
  • 1975-1979
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  • 1
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    Institutional arrangements for the space telescope: A mid-term review (1985)
    In:  CASI
    Details
    Publication Date: 2005-03-01
    Keywords: ASTRONOMY
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  • 2
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    Interplanetary shock phenomena beyond 1 AU (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Attention is given to spatial dependences exhibited by spacecraft measurements obtained between 1 and 30 AU, together with temporal variations occurring between solar activity cycle maxima and minima. At 1-3 AU radial distances, shocks develop in association with the corotating solar wind streams characterizing solar minimum and accelerate solar wind evolution with distance while heating the solar wind and generating waves and turbulence. At solar maximum, shocks are observed more frequently at 1 AU but still in association with transient solar events; acceleration leading to energetic storm particles is observed both within and beyond 1 AU. The superimposed effect of large numbers of intense shocks may be responsible for the solar cycle modulation of galactic cosmic rays.
    Keywords: ASTROPHYSICS
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  • 3
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    Nucleus studies of Comet Halley (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Early results from, and research initiatives warranted by, the earth-based observations of Halley's near-nucleus and related phenomena are reviewed. Where appropriate, this information is combined with spacecraft data obtained by the various flight projects. The basic objective is to gain a greater insight into the nature of the comet's nucleus and its environment.
    Keywords: ASTROPHYSICS
    Type: Advances in Space Research (ISSN 0273-1177); 5; 12, 1; 307-316
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  • 4
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    Preliminary results of the Giotto radio science experiment (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Doppler and ranging measurements using the radio signal of the Giotto spacecraft were taken before, during, and after the encounter with Comet Halley on Mar. 13, 14, 1986. The spacecraft velocity was found to decrease by a total of 23.3 cm/s due to impacting gas and (primarily) dust in the cometary atmosphere. A preliminary dust production rate of 1000 kg/s is found to be consistent with this deceleration. Power spectra of the carrier phase fluctuations reveal an increase in level and a flattening of the spectrum just prior to encounter, presumably associated with the enhanced dust impact rate. Finally, simulated Doppler time profiles are computed using the radial dependence of plasma density observed by the Giotto in situ investigations. It is shown that the cometary electron content profile would have been clearly seen if a dual-frequency downlink radio configuration had been available at encounter.
    Keywords: ASTROPHYSICS
    Type: Advances in Space Research (ISSN 0273-1177); 5; 12, 1
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  • 5
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    A preliminary look at the dust in Comet Halley (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Highlights of infrared observations of the dust are discussed and compared with first results from the space probes. An emission feature was detected at 3.4 microns; the 10 and 20 micron silicate features were well-observed; and far-infrared data out to 160 micron were obtained. Organic material seems to be abundant in grains and may explain the 3.4 micron emission. Calculations are presented for one example of organic material. A component of the grains may volatize at temperatures around 300 K.
    Keywords: ASTROPHYSICS
    Type: Advances in Space Research (ISSN 0273-1177); 5; 12, 1; 325-334
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  • 6
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    Cometary kilometric radio waves and plasma waves correlated with ion pick-up effect at Comet Halley (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Bow-shock movements at Comet Halley are inferred from the discrete spectra of the cometary kilometric radiation (30-195 kHz); the observed emissions can be interpreted as being generated and propagating from the moving shock. The shock motion is possibly associated with the time variation of the solar wind and cometary outgassing. It is concluded that these plasma wave phenomena are manifestations of ion pick-up processes, which occur even in a remote region 7 million to 10 million km from the cometary nucleus.
    Keywords: ASTROPHYSICS
    Type: Advances in Space Research (ISSN 0273-1177); 5; 12, 1; 83-88
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  • 7
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    The identification of H2311 + 77 with HD220140, a probable RS CVn star (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: H2311 + 77, one of the bright soft X-ray sources in the sky originally detected with HEAO 1, has been identified in an Exosat imaging observation with a 7.7-mag late-type star, HD220140. The X-ray luminosity and the optical characteristics of this star indicate that it is probably an RS CVn binary system.
    Keywords: ASTRONOMY
    Type: Royal Astronomical Society, Monthly Notices (ISSN 0035-8711); 215; 11P-13P
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  • 8
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    CNO isotopes in red giant stars (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Observational data on CNO abundance ratios in red giants and the interstellar medium (ISM) are analyzed for the implications for the production and distribution of CNO nuclides. The data included isotope abundance measurements for the atmospheres and recent ejecta of cool giants, e.g., carbon stars, S-type stars, red supergiants and oxygen-rich giants beginning an ascent of the giant branch. The contribution of intermediate-mass stars to galactic nuclear evolution is discussed after comparing red giant abundances with ISM abundances, particularly the isotopes O-16, -17 and -18. The O-12/O-18 ratios of red giants are distinctly different from those in interstellar molecular clouds. The CNO values also vary widely from the values found in the solar system.
    Keywords: ASTROPHYSICS
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  • 9
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    CNO abundances in novae ejecta (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Isotope production, particularly CNO, which are enhanced in novae events and the interstellar medium (ISM) by novae are discussed in terms of emission-line data taken a few weeks after novae events. The emission-line abundances emerge only after the fading of absorption spectrum, and are also detectable in thin shells which sometimes, though rarely, form after novae. CNO abundances in these shells are equivalent to those observed in fading novae, with CNO/H ratios being 100 times solar values. Possible heavy element production pathways in the events and their shrinking are discussed, along with observation techniques for detecting CNO isotopes through absorption data on atomic transitions in novae ejecta and the ISM.
    Keywords: ASTROPHYSICS
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  • 10
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    An analysis of IRAS' solar system dust bands (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Measurements of longitudinal variations in the brightness and in the latitude of the solar system dust bands recently discovered by IRAS will determine the orbital elements of the particles involved and may discriminate between cometary and asteroidal models of the origin of these bands. The expected variations for bands of dust particles with common orbital elements and small eccentricity and inclination are calculated as functions of semimajor axis.
    Keywords: ASTROPHYSICS
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  • 11
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    Mass input into and output from the meteoritic complex (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The consequences which arise from the mutual collisions occurring between interplanetary meteoroids, the Poynting-Robertson (PR) effect and the radiation pressure ejection of small meteoroids are examined. The size distribution and flux of micrometeoroids at 1 AU are derived and the dependence of spatial density on distance from the sun is established. The following conclusions are made: (1) the lifetimes of meteoroids with masses approximately greater than 0.00001 g are dominated by catastrophic collisions; (2) after bering crushed by collisions, 70 to 85 percent of this mass will be in the form of zodiacal light particles (with masses in the range of 10 to the -10th g to 10 to the -5th g) which will in part be transported by the PR effect towards the sun where they will evaporate; (3) the 15 to 30 percent of the collisional fragments which have masses approximately less than 10 to the -10th g will, for the most part, be injected into hyperbolic orbits by radiation pressure.
    Keywords: ASTROPHYSICS
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  • 12
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    Optical detection of large meteoroids in space (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: CCD sensors placed across the focal plane of large Schmidt telescopes have great potential for detecting and measuring the very low flux in space of meteoroids with diameters larger than 1 meter. With the Palomar 'Big Schmidt', a detection rate of 1.4 per hour is obtained for meteoroids between 0.6 and 200 meters in diameter. For the Baker-Nunn 'Satellite Tracking Camera', the corresponding rate is about 0.8 per hour. The key to obtaining such high detection rates derives from approximately setting the sensor integration time equal to the time it takes a meteoroid to cross a pixel field of view. This minimizes signal to noise problems and is accomplished, in practice, by multiple summing of short integration time data records to obtain data records of longer effective integration times.
    Keywords: ASTRONOMY
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  • 13
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    Selection effects against small comets (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Everhart's (1967) formulation is used to determine the correlation between the probability of discovering a comet and the size of its nuclear radius. The analysis is concentrated on comets that are not more than two or three hundred meters in diameter; hence, heliocentric variations in cometary brightness can be neglected. The effect of cometary physical decay is also considered, and a strong observational bias against the detection of small active comets is found. The following three factors are involved: (1) small comets must pass closer to the earth than large comets in order to be detected, (2) the resulting higher angular velocity for nearby comets leads to a decrease in the time available to discover a small comet, and (3) small comets physically decay and vanish faster than do large comets.
    Keywords: ASTROPHYSICS
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  • 14
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    IRAS observations of the interplanetary dust emission (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The Infrared Astronomical Satellite (IRAS) has completed a sensitive, highly redundant survey of the full sky in four broad photometric bands at 12, 25, 60, and 100 micrometers wavelength. The survey measured interplanetary dust emission over elongation angle ranging from 60 to 120 degrees. Bright emission from the main cloud is consistent with optically thin blackbody emission. The grains are evidently quite black, with an 'apparent albedo' of about 0.07. The data show clear evidence for deviation of the dust symmetry surface from the ecliptic plane. Surprising bands of emission were discovered near the ecliptic plane and about ten degrees on either side of it. The heliocentric distance of this material, suggested to be asteroidal in origin, is inferred to be about 2.5 AU from both color temperature and parallax measurements.
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  • 15
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    Large and small scale structures of molecular clouds in the Taurus Perseus complex (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The gaseous components studied in H I and OH absorption against the extragalactic radiosources 3C123 and 3C111 are found to be the low-density edges of condensations of a few 100 solar masses. The densest part of one of these condensations has a structure similar to that found in other dark clouds: it is fragmented into several cores of a few solar masses, with an orbital velocity dispersion of about 2 km/s. In turn, the extended low-density layer, optically thick in CO (2-1), is not a common feature. It depends on the ambient UV field, but the dust temperature in the core may control its existence. Even more critically; it is found that the lower is the dust temperature, the less massive is the core and the more extended is the envelope around it, for a given total mass in a given external pressure.
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  • 16
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    On the orientation of ephemeris reference frames (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Precession corrections, equinox motions and locations, and obliquities for the FK4 are determined from laser-ranging data only by the ephemeris-fitting method of Standish (1982) and compared with those calculated by Fricke (1971 and 1982) from optical observations. The theoretical basis of the comparison is explained, and the results are presented in a table. No significant differences are found in the equinox offset and equinox motion values, and good agreement is found in the equinox location. The ephemeris-fitting obliquity values are shown to be consistent to within 10 marcsec and to be about 20 marcsec lower than the optical values.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics (ISSN 0008-8714); 37; 239-242
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  • 17
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    The evolution of adopted values for precession (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The history of astronomical longitude precession determination is reviewed. Consideration is given to the work of Hipparchus and Ptolemy, the definition of rotation axes, the major 19th-century determinations, and 20th-century studies (using the data of Newcomb; based on PGC, GC, and McCormick/Cape catalogs; using FK3, FK4, and AGK3; involving galaxies; and using the dynamical method). Laser ranging and VLBI are seen as the most promising techniques for future precession measurements. Diagrams, graphs, and tables of numerical data are provided.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics (ISSN 0008-8714); 37; 209-238
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  • 18
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    Cepheid variables as extra-galactic distance indicators (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The role of Cepheid variables in establishing the inner distance scale to nearby galaxies is discussed. Emphasis is placed on the necessity for broad wavelength coverage in attempting to account for metallicity differences and reddening internal to the parent galaxies. In addition linear detectors are essential in minimizing the effects of any unresolved background contribution to the photometry. Recent infrared observations of Cepheids in Local Group galaxies are surveyed and all published data on extra galactic Cepheids are presented for convenient access.
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  • 19
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    The 50 millisecond pulsar in the Large Magellanic Cloud and the X-ray pulse emission mechanism (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: ASTROPHYSICS
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  • 20
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    Interstellar clouds - From a dynamical perspective on their chemistry (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The possibility is examined that in the course of its dynamical evolution, a single mass of interstellar gas would exhibit properties of diffuse clouds, dense clouds and finally also of clouds perturbed by shocks or intense UV or X-ray radiation generated by a star of its own creation. This concept provides a common thread through the bewildering diversity of physical and chemical compositional properties shown by interstellar clouds. From this perspective, instead of being static objects, interstellar clouds are possibly incessantly evolving from initially diffuse to later dense state and then to star formation which ultimately restructures or disperses the remaining cloud material to begin the whole evolutionary process once again. Based on a simplified study of interstellar chemistry from a dynamical perspective, the ideas are presented as an heuristic: to encourage thought on the future direction of molecular astrophysics and the need to consider the chemical behavior of interstellar clouds in conjunction with, rather than in isolation from, their dynamical behavior. A physical basis must be sought for the semiempirical temperature formula which has been given a critical role in the collapse of diffuse clouds. Self-shielding effects in the chemistry of CO were neglected and this drawback should be removed; the ability of the model to explain the fractional abundances of more complex molecules, such as cyanopolyynes, should be examined.
    Keywords: ASTROPHYSICS
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  • 21
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    Cometary comae (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The basis of our knowledge about the structure and composition of a comet nucleus is examined. Such knowledge is inferred from observations of the cometary atmosphere (coma). However, photodissociation, photoionization, and chemistry destroy the mother molecules evaporating from the nucleus. To extract the primary information, the chemical kinetics and the physics of the coma are modeled with a computer and the results are compared with coma observations. The physics and chemistry for a dust free coma are described taking into account energy balance, multi-fluid flow for fast atomic and molecular hydrogen and the bulk fluid, and the transition from a collision dominated inner region to the free molecular flow outer region. Special attention is paid to the molecular data requirements for the current modeld and for extended models which will include solar wind interaction and dust. Such models are an important tool in support of the Giotto mission to Halley's comet, in the analysis and interpretation of coma observations, and in the understanding of the earliest history of the solar system.
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  • 22
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    Protoplanetary material around nearby stars (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A statistical analysis of IRAS observations indicates that about 20 percent of the nearby main sequence stars, and probably a similar fraction of main sequence stars not detectable by IRAS, shows evidence of significant infrared excess beyond 12 microns. Spectral type A dwarfs are predominant, but not exclusive in showing large 60-micron excesses. The solar system, when viewed from sufficient distance, appears to have, in contrast to this, less than 1 percent of cool infrared excess. These observational facts are consistent with the working hypothesis that cold infrared excess in stable main sequence stars is due to protoplanetary material, observable during the accretion phase in the evolution of a solar system.
    Keywords: ASTRONOMY
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  • 23
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    Assisting extrasolar planetary detection through the determination of stellar space orientations (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Various methods outlined for indirect planetary detection would greatly benefit (in some cases require) the determination of the planetary orbital plane, which is theoretically equivalent to the stellar equatorial plane. Determining the stellar space orientation, therefore, would greatly benefit extrasolar planetary detection. Stellar rotation periods determined from short-term variations in Ca II H and K sunspot emission are utilized together with both stellar radii measurements and Doppler-broadened spectral line profiles to get the stellar inclination to the line of sight. The clocklike on-the-plane-of-the-sky component determination utilizes the concentration of sunspot-associated plage areas at central stellar latitudes when viewed in Ca II H or K emission. One can perform Ca II H and K emission speckle interferometry to measure the clocklike angle of this stellar Ca II H and K emission band, modeling it as an elliptical intensity distribution. Both components should be determinable to within 10 deg for at least the resolvable fifth magnitude stars.
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  • 24
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    Problems with interpreting the radio emission from hot stars (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Problems in hot star radio emission interpretation due to radio flux source and other modeling assumptions are examined. An upper limit constraint on the value of the mass loss rate divided by the constant wind velocity is imposed by assuming that the outflow is due to bremsstrahlung in a spherically symmetric wind with the stationary photosphere visible at 4500 A, and by the need for it to be less than the luminosity divided by c. The constraints are satisfied for the deduced values for OB supergiants, and to some extent for early 0 stars, but not for Wolf-Rayet stars, due to mass loss rates excessive by a factor of 10. It is suggested that the problem can be solved by postulating that part of the radio flux from Wolf-Rayet stars is due to processes in a low-density magnetized plasma.
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  • 25
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    Dynamical evolution of the Oort cloud (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: New studies of the dynamical evolution of cometary orbits in the Oort cloud are made using a revised version of Weissman's (1982) Monte Carlo simulation model, which more accurately mimics the perturbation of comets by the giant planets. It is shown that perturbations by Saturn and Jupiter provide a substantial barrier to the diffusion of cometary perihelia into the inner solar system. Perturbations by Uranus and Neptune are rarely great enough to remove comets from the Oort cloud, but do serve to scatter the comets in the cloud in initial energy. The new model gives a population of 1.8 to 2.1 x 10 to the 12th comets for the present-day Oort cloud, and a mass of 7 to 8 earth masses. Perturbation of the Oort cloud by giant molecular clouds in the galaxy is discussed, as is evidence for a massive 'inner Oort cloud' internal to the observed one. The possibility of an unseen solar companion orbiting in the Oort cloud and causing periodic comet showers is shown to be dynamically plausible but unlikely, based on the observed cratering rate on the earth and moon.
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  • 26
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    A new emission feature in IRAS spectra and the polycyclic aromatic hydrocarbon spectrum (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: IRAS spectra of those sources which show strong 7.7 and 11.3 micron emission features also show a plateau of emission extending from 11.3 to about 13.0 microns. Like the 11.3 micron feature, this new feature is attributed to the CH out-of-plane bending mode in polycyclic aromatic hydrocarbons (PAHs). Its discovery reinforces the identification of the 'unidentified infrared emission features' as emission from PAHs. The wavelength of this new feature suggests that interstellar PAHs are not as partially hydrogenated as hitherto thought. It also constrains their molecular structure.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X); 299; L93-L97
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  • 27
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    Near-infrared mapping of ARP 299 (IC 694-NGC 3690) - Colliding galaxies unveiled (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Near-infrared maps and multicolor photometry of the interacting galaxies IC 694 and NGC 3690 which form Arp 299 (= Markarian 171) are presented. These data reveal for the first time the distribution of nuclei and old red stars in a cataclysmically interacting system. The nuclei are considerably offset from the visual centroids of the galaxies but not from the mass centroids. The near-infrared colors of the most active regions are strongly affected by extinction, emission form hot dust, and bremsstrahlung. Near-infrared emission is also identified with secondary regions of star formation, probably resulting from the galaxies' interaction.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 299; 896-904
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  • 28
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    Molecular cloud evolution and star formation (1985)
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    Publication Date: 2011-08-19
    Description: The present state of knowledge of the relationship between molecular clouds and young stars is reviewed. The determination of physical parameters from molecular line observations is summarized, and evidence for fragmentation of molecular clouds is discussed. Hierarchical fragmentation is reviewed, minimum fragment scales are derived, and the stability against fragmentation of both spherically and anisotropically collapsing clouds is discussed. Observational evidence for high-velocity flows in clouds is summarized, and the effects of winds from pre-main sequence stars on molecular gas are discussed. The triggering of cloud collapse by enhanced pressure is addressed, as is the formation of dense shells by spherical outflows and their subsequent breakup. A model for low-mass star formation is presented, and constraints on star formation from the initial mass function are examined. The properties of giant molecular clouds and massive star formation are described. The implications of magnetic fields for cloud evolution and star formation are addressed.
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  • 29
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    Far-infrared and submillimeter photometry of evolved stars (1985)
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    Publication Date: 2011-08-19
    Description: Broad-band photometric observations at far infrared and submillimeter wavelengths (lambda is greater than 30 microns and less than 1) provide a unique probe of circumstellar shells in evolved objects and of the mass loss processes which produce them. The problems which these observations explore include: dust properties and dust-to-gas ratios in the outflowing material, the mass and structure of the circumstellar shell, and the pumping mechanism for maser emission. This contribution reviews the early work in this still largely unexploited field and reports results in each of the areas listed above. The dramatic advances forthcoming in this area from the IRAS satellite are previewed along with further progress which will come from the next generation of infrared and submillimeter telescopes.
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  • 30
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    Mass loss from red giants - Infrared spectroscopy (1985)
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    Publication Date: 2011-08-19
    Description: A discussion is presented of IR spectroscopy, particularly high-resolution spectroscopy in the approximately 1-20 micron band, as it impacts the study of circumstellar envelopes. The molecular bands within this region contain an enormous amount of information, especially when observed with sufficient resolution to obtain kinematic information. In a single spectrum, it is possible to resolve lines from up to 50 different rotational/vibrational levels of a given molecule and to detect several different isotopic variants. When high resolution techniques are combined with mapping techniques and/or time sequence observations of variable stars, the resulting information can paint a very detailed picture of the mass-loss phenomenon. To date, near-IR observations have been made of 20 molecular species. CO is the most widely observed molecule and useful information has been gleaned from the observed rotational excitation, kinematics, time variability and spatial structure of its lines. Examples of different observing techniques are discussed in the following sections.
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  • 31
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    The infrared characteristics of circumstellar silicate grains (1985)
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    Publication Date: 2011-08-19
    Description: A theoretical study of the infrared emission from circumstellar shells around late-type giants is made, with the aim of deriving the infrared characteristics of the silicate grains condensing in these shells. A large grid of models has been compared with observations of optically visible Miras, IRC sources and OH/IR stars. From fitting the observed relation between the color temperature and the strength of the 10-micron feature, it is concluded that the ratio of the 3.5 to 10-micron absorption efficiencies of the dust is about 0.25, a factor of 2 less than a previous determination. Detailed modeling of the 2 to 13-micron spectrum of OH 26.5 + 0.6, IRC + 10011 and R Cas yielded a similar ratio. These detailed models also show that the shape of the 10-micron feature, particularly around 8 and 13 microns, varies from source to source. The derived 10-micron feature is narrower for larger dust column densities. These observed differences in the intrinsic shape of the 10-micron feature are not due to differences in size of the condensing particles. Probably they are related to structural or compositional differences in the condensing silicates.
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    Protostellar angular momentum transport by spiral density waves (1985)
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    Publication Date: 2011-08-19
    Description: The application of rotational stability criteria to a specific model of star formation leads to the conclusion that the growth of stellar angular momentum is limited by its transfer to the disk. Excess accreted angular momentum can be transferred by torques connected with spiral density waves induced by even a slight protostellar triaxiality. In addition, viscous damping of the density waves is likely to cause the excess angular momentum to be deposited within a small region close to the protostar. Thus, it would be appropriate to treat that part of the growing protostellar disk beyond the outer Lindblad resonance as an accretion disk with a torque applied to its inner edge. It is noted that this situation is directly relevant to certain models of the evolution of the protosun and solar nebula.
    Keywords: ASTROPHYSICS
    Type: Icarus (ISSN 0019-1035); 64; 435-447
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    The plasma regime at comet Giacobini-Zinner (1985)
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    Publication Date: 2011-08-19
    Description: The paper reviews results on the plasma regime at Comet Giacobini-Zinner obtained by the International Cometary Explorer. The observations are consistent with the existence of a weak shock which may be pulsating, but do not exclude the suggestion that the shock, though present around the subsolar point, is an the process of decaying to a wave on the flanks. 'The pick-up' of cometary ions leads to ion cyclotron, mirror, beam, and electrostatic instabilities which cause strong turbulence in the inner coma.
    Keywords: ASTROPHYSICS
    Type: Advances in Space Research (ISSN 0273-1177); 5; 12, 1
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    Layered synthetic microstructures for solar EUV telescopes (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The application of layered synthetic microstructures (LSMs) to figured mirrors suitable for normal incidence solar EUV telescopes is considered, and initial studies for a single mirror telescope consisting of an f/18, 200-cm focal length off-axis paraboloid demonstrate the feasibility of LSM coatings for moderate sized mirrors. Analytical studies on broadband designs comprised of five layers show a seven percent reflectance at 256 A and reflectivities of over 12 percent for wavelengths above 300 A. Deposition considerations are also discussed.
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    The status of low-energy gamma-ray astronomy and the Gamma-Ray Observatory (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A brief sketch of the objectives and status of the various subdisciplines in gamma-ray astronomy (below 10 GeV) are presented. The Gamma-Ray Observatory planned for launch in 1988 is described. This NASA observatory and several planned French-Soviet spacecraft are expected to elevate gamma-ray astronomy into a mature observational science for the Space Station era.
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    Ammonia in the hot galactic centre cloud G 1.6-0.025 (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: As part of an extensive southern survey of interstellar NH3 with the Parkes 64-m radio telescope (with a beamwidth of 81 arcsec), the (1,1), (2,2), and (3,3) transitions have been observed towards the galactic centre molecular cloud Gl.6-0.025. The cloud has an overall size of 10 arcmin, and contains several concentrations with differing velocities. It has several features also observed in other galactic centre clouds, e.g. high optical depths and kinetic temperatures above 50 K.
    Keywords: ASTROPHYSICS
    Type: Astronomical Society of Australia, Proceedings (ISSN 0066-9997); 6; 2, 19
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    A calculation of the Rosseland mean opacity of dust grains in primordial solar system nebulae (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The Rosseland mean opacity owing to grains was calculated as a function of temperature and density for nebulae having solar elemental abundances. The values of the mean opacity were evaluated with a generalized formulation allowing for anisotropic scattering. The values of the mean opacity do not depend sensitively on the choice of the particle size distribution function, provided that there are few particles having sizes in excess of several tens of microns. The results indicate that thermal convection in primordial nebulae occurs over broader ranges of altitudes at low temperatures than at high temperatures, and for size distributions for which extensive aggregation has not yet occurred.
    Keywords: ASTROPHYSICS
    Type: Icarus (ISSN 0019-1035); 64; 471-492
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    Diagnostics of solar and astrophysical plasmas - Dependent on autoionization phenomena (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The application of autoionization calculations to problems in solar and astrophysical plasma diagnostics is discussed. Attention is given to space plasmas having high spectral resolution, particularly in the wavelength region between about 300 and 1100 A. It is shown that atomic resonance data can be used to calculate many of the spectral line intensities in solar plasmas in order to obtain information concerning the physical properties of the emitting gas, including temperature, density, ionization balance, and atmospheric structure and dynamics. Recent spectral observations of nonsolar plasmas are also discussed. A list of the major high-resolution astrophysical plasma spectrometers and spectrographs is provided.
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    Anatomy of a cosmic-ray neutrino source and the Cygnus X-3 system (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The effects of an intense beam of ultra-high energy cosmic rays from a compact object in the Cygnus X-3 binary system hitting the companion star, and of the subsequent production of secondary neutrinos, are examined. A maximum allowable beam luminosity of about 10 to the 42nd erg/s is found for a system containing a 1-10 solar mass main sequence target star. The proton beam must heat a relatively small area of the target star to satisfy observational constraints on the resulting stellar wind. With such a model, the neutrino to gamma-ray flux ratio of about 1000 can result from a combination of gamma-ray absorption and a large neutrino to gamma-ray duty cycle ratio. It is found that the high density of the atmosphere resulting from compression by the beam leads to pion cascading and a neutrino spectrum peaking at 1-10 GeV energies.
    Keywords: ASTROPHYSICS
    Type: Nature (ISSN 0028-0836); 316; 418-420
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    Pedestal features in dark clouds - A search for radio emission (1985)
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    Publication Date: 2011-08-19
    Description: Radio emission associated with broad-winged CO sources in B335, L1527, L1455, and L732 was searched for. No detections were made in three of the sources, B335, L1527, and L732. A nonthermal double radio source was found near the focus of the L1455 flow. This source is probably associated with the flow, and may represent a new aspect of the molecular flow phenomenon.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 295; 89-93
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    The physical implications of an isothermal model for the hot intracluster medium (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: HEAO-1 A-2 and Einstein Observatory IPC observations of 15 clusters of galaxies have been used to measure the isothermal beta-model parameters, and the parameters are compared with those derived from model fits to the X-ray images. The physical constraints imposed on this model by existing optical data, the implied gas mass, and the gas contribution to the binding cluster mass are addressed. Values of beta less than unity are obtained, consistent with results from X-ray imaging data. This is interpreted to imply that the gas extends out to 8-10 core radii, about 2-3 Mpc. The isothermal gas mass can be as large as 60 percent of the virial mass for some clusters. This contradicts the fundamental assumption that the cluster potential is determined by an unseen mass which is given by the King approximation to an isothermal sphere, and it is concluded that the isothermal model is a nonphysical model.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 292; 441-446
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  • 42
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    High-energy X-ray observations of the Galactic center region (1985)
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    Publication Date: 2011-08-19
    Description: The region within five degrees of the Galactic center was observed in high-energy X-rays on November 12, 1977, and it is concluded that the emission definitely comes from more than one source. At least five 2-10 keV sources are important: the transient A1743 - 322, the binary GX 1 + 4, the bulge sources GX 3 + 1 and GX 5 - 1, and A1742 - 294. The composite spectrum of all the sources agrees with the continuum measured 12 days earlier by Leventhal, MacCallum, and Stang (1978) in the 70-250 keV range but, if extrapolated to higher energies, would be softer than and weaker than the HEAO 1 continuum observed in September 1977 or HEAO 3 continuum observed in the fall of 1979.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 290; 557-567
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    On fast X-ray rotators with long-term periodicities (1985)
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    Publication Date: 2011-08-19
    Description: The support of previous SAS 3 spacecraft observations by new data gathered by the Monitor Proportional Counter aboard the HEAO 2 spacecraft indicates that the pulse period history of the 13.5 sec-pulsing X-ray source LMC X-4 is consistent with standard accretion and torque models only if LMC X-4 is a fast rotator for which the accretion torques nearly cancel. This result leads to a neutron star magnetic field strength estimate of about 1.2 x 10 to the 13th G. Strong evidence is noted for Her X-1's status as a fast rotator, while SMC X-1 is probably an intermediate-to-fast rotator. In the context of slaved disk models for these objects, it is noted that the precession periods expected for the companion stars are significantly longer than the observed 1-2 month time scales; slaved disk models are thereby undermined.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 290; 487-495
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    Electrosphere of an aligned magnetized neutron star (1985)
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    Publication Date: 2011-08-19
    Description: A fundamentally new self-consistent solution for the electrosphere of an aligned magnetized neutron star is presented. Unlike previous models the electrospheres are finite in extent. This avoids the light cylinder problem. The results may provide a basis for pulsar models.
    Keywords: ASTROPHYSICS
    Type: Royal Astronomical Society, Monthly Notices (ISSN 0035-8711); 213; 43P-49P
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    Cometary impacts, molecular clouds, and the motion of the sun perpendicular to the galactic plane (1985)
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    Publication Date: 2011-08-19
    Description: The stochastic nature of the mass extinction model of Rampino and Stothers (1984), based on the vertical oscillation of the solar system about the plane of the Galaxy, can accommodate a few events with large phase discrepancies. The degree of modulation is crucial in that it depends on the scale height of the population of molecular clouds relative to the amplitude of the solar system and tends to zero if this ratio is large and encounters are entirely random. Here data are presented here from CO surveys of molecular clouds both within and beyond the solar circle which permit explicit calculation of the strength of the modulation. The cloud layer near the sun it too extended and, as a consequence, the modulation of cloud encounters is too weak for a statistically significant period to be extracted from the nine extinctions analyzed by Rampino and Stothers.
    Keywords: ASTRONOMY
    Type: Nature (ISSN 0028-0836); 314; 73-75
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    MgS grain component in circumstellar shells (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: In this letter, far-infrared spectrophotometry (30-55 microns) and photometry (53-200 microns) are presented which define, for the first time, the long wavelength limit of the previously unidentified 30 micron emission feature found in certain extreme carbon star spectra. The spectral similarities are sufficiently similar to those of solid MgS that MgS is proposed to be the band carrier. This is interpreted as the first direct evidence that chemical surface reactions occur on dust grains in circumstellar environments. The presence of MgS indicates that either the oxygen abundance is relatively low and/or the sulfur abundance is high in extreme carbon stars.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X); 290; L35-L39
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    Laboratory infrared spectra of predicted condensates in carbon-rich stars (1985)
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    Publication Date: 2011-08-19
    Description: Laboratory spectra and mass absorption coefficients of MgS, CaS, FeS, SiS2, FeS2, Fe3C, and a commercial iron carbide are presented over the wavelength range 125-15 microns. These spectra confirm that MgS is the most likely source of the unidentified 30-micron emission in carbon-rich sources and that FeS, Fe3C, and 'iron carbide' cannot be responsible for this feature although they could contribute to the continuum in this region. CaS and FeS2 may contribute to the 30-micron feature; however, both higher resolution and higher precision astronomical observations are needed before their presence can be established. SiS2 has a peak near 22 microns and therefore cannot be a significant component of the dust in such regions.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X); 290; L41-L43
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    Polycyclic aromatic hydrocarbons and the unidentified infrared emission bands - Auto exhaust along the Milky Way (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The unidentified infrared emission features (UIR bands) are attributed to a collection of partially hydrogenated, positively charged polycyclic aromatic hydrocarbons (PAHs). This assignment is based on a spectroscopic analysis of the UIR bands. Comparison of the observed interstellar 6.2 and 7.7-micron bands with the laboratory measured Raman spectrum of a collection of carbon-based particulates (auto exhaust) shows a very good agreement, supporting this identification. The infrared emission is due to relaxation from highly vibrationally and electronically excited states. The excitation is probably caused by UV photon absorption. The infrared fluorescence of one particular, highly vibrationally excited PAH (chrysene) is modeled. In this analysis the species is treated as a molecule rather than bulk material and the non-thermodynamic equilibrium nature of the emission is fully taken into account. From a comparison of the observed ratio of the 3.3 to 11.3-micron UIR bands with the model calculations, the average number of carbon atoms per molecule is estimated to be about 20. The abundance of interstellar PAHs is calculated to be about 2 x 10 to the -7th with respect to hydrogen.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X); 290; L25-L28
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    The R Aquarii system at optical and radio wavelengths (1985)
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    Publication Date: 2011-08-19
    Description: New continuum observations of all radio components of the R Aquarii system at 2, 6, and 20 cm are reported which allow determination of polarization properties, integrated flux levels, spectral indices, and hence the emission mechanisms of the individual components. Complementary wide-band optical observations are also reported to help determine the nature and structure of the compact double radio source (CDRS) and the R Aquarii radio jet. The results of these observations are discussed in detail with regard to models currently or previously proposed for the R Aquarii system. It is concluded that the compact H II region spectral index is about +0.6, indicative of a thermal and optically thick expanding wind from the long-period variable. The radio jet emission is shown to be optically thin, thermal, cospatial with optical emission, and stable over the last few years. The CDRS is shown to be an extragalactic background object.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 289; 765-767
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    Tail phenomena (1985)
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    Publication Date: 2011-08-19
    Description: An overview of tail phenomena is presented based on worldwide submissions to the Large-Scale Phenomena Discipline Specialist Team of the International Halley Watch. Examples of tail phenomena and science are presented along with estimates of total expected yield from the Network. The archive of this material will clearly be very valuable for studying the solar-wind/comet interaction during the 1985-1986 apparition of Halley's Comet.
    Keywords: ASTRONOMY
    Type: Advances in Space Research (ISSN 0273-1177); 5; 12, 1
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    High-angular resolution observations of stellar binary systems (1985)
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    Publication Date: 2011-08-19
    Description: A long-term program designed to investigate the spatial structure of centimetric radio emission from close binary systems using multistation VLBI array is discussed. Eleven binaries, including eight RS CVn systems, Algol, LSI 61 deg 303, and Cyg X-1, have been detected. The measured brightness temperatures vary from T(B) about 10 exp 8.5 K during periods of low activity to T(B) about 10 exp 10.5 K during flares. Extensive observation of a few sources has shown that the spatial structure is 'core-halo' with linear dimensions of about a stellar radius and the binary system, respectively. The observations are consistent with gyrosynchrotron emission of mildly relativistic electrons in magnetic fields of about 10 exp 1.5 + or - 0.5 gauss. The core sources appear to be optically thick, while the halo component is optically thin.
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    The dynamical history of comet Halley (1985)
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    Publication Date: 2011-08-19
    Description: The history of the attempts to predict the motion of comet Halley is outlined and the importance of the so-called nongravitational forces acting upon this comet is emphasized. Recent orbital work of the International Halley Watch Astrometry Network is reviewed. Comet Halley's transverse nongravitational parameter is positive and nearly constant with time suggesting that the comet is in direct rotation without precession of the spin pole. The nongravitational effects are consistent with the vaporization of water ice from the comet's nucleus and long term integrations suggest that the comet has been in its present orbit for at least 16,000 years and probably much longer.
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    Morphological and physical characteristics of the Virgo Cluster - First results from the Las Campanas photographic survey (1985)
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    Publication Date: 2011-08-19
    Description: Preliminary results are presented of a photographic survey of the Virgo cluster to the faintest convenient limit of the Las Campanas du Pont 2.5 m reflector, performed in order to study the complexity of both the surface and velocity distributions within the central 6 degree radius region. The survey is described and the resulting Catalog is discussed, and the frequency of galaxy types found and listed in the Catalog is described. The physical properties of the dwarfs are summarized, and luminosity functions are given separately for each morphological type. The progressive change of (MBT) faintward along the morphological sequence from Sc I through Sm and Im types is shown, leading to a calibration of the de Vaucouleurs Lambda luminosity index and a determination of its intrinsic dispersion. The preliminary results on the distribution of galaxies of all types in the two principal subclustering regions found are summarized, and the velocity distributions over the face of the 6 degree core are discussed for the various galaxy types.
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    8.3 and 12.4 micron imaging of the Galactic Center source complex with the Goddard infrared array camera (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A 30 x 30 arcsec field at the Galactic Center (1.5 x 1.5 parsec) was mapped at 8.3 microns and 12.41 microns with high spatial resolution and accurate relative astrometry, using the 16 x 16 Si:Bi accumulation mode charge injection device Goddard infrared array camera. The design and performance of the array camera detector electronics system and image data processing techniques are discussed. Color temperature and dust opacity distributions derived from the spatially accurate images indicate that the compact infrared sources and the large scale ridge structure are bounded by warmer, more diffuse material. None of the objects appear to be heated appreciably by internal luminosity sources. These results are consistent with the model proposing that the complex is heated externally by a strong luminosity source at the Galactic Center, which dominates the energetics of the inner few parsecs of the galaxy.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 299; 1007-101
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    Bipolar nebulae and mass loss from red giant stars (1985)
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    Publication Date: 2011-08-19
    Description: Observations of several bipolar nebulae are used to learn something of the nature of mass loss from the probable red-giant progenitors of these nebulae. Phenomena discussed are: (1) probable GL 2688's optical molecular emissions; (2) newly discovered very high velocity knots along the axis of OH 0739 - 14, which reveal evidence for mass ejections of + or 300 km/s from the M9 III star embedded in this nebula; (3) the bipolar structure of three extreme carbon stars, and the evidence for periodic mass ejection in IRC + 30219, also at high speed (about 80 km/s); and (4) the curious cool TiO-rich region above Parsamian 13, which may represent the very recent shedding of photospheric material from a cool, oxygen-rich giant. Several general key questions about bipolar nebulae that relate to the process of mass loss from their progenitor stars are raised.
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    Infrared studies of the bipolar nebula OHO739 (1985)
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    Publication Date: 2011-08-19
    Description: Infrared studies have been made of the M9 giant OHO739, which is embedded in a bipolar nebula, in order to study the structure and density distribution of the circumstellar disk, and preliminary results are reported. The degree of polarization across the 3.1 micron ice band in an 8 arcsec beam centered at the 2.2 micron peak is found to increase with extinction in the ice band, as expected for a bipolar scattering nebula. A distance of 2 kpc is inferred from the tilt angle of the bipolar axis and phase lag measurements of the OH maser. Maps made in the K band and in narrow bands at 2.85, 3.1, and 3.5 microns by raster-scanning OHO739 are presented. In all maps, the object is clearly elongated along the bipolar axis. Patterns of increases and decreases in extinction in the object are inferred to indicate that ice particles are widespread through the nebula and not just concentrated in the disk.
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    Hydrogen deficiency and mass loss from AGB stars (1985)
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    Publication Date: 2011-08-19
    Description: Theoretical studies predict that mass loss from stars should accelerate once stars on the AGB begin thermal pulsations (TP). It has been discovered that the stars on this part of the AGB are apparently hydrogen deficient. This development may be related to the mass loss predicted by theory. Hydrogen deficiency is also supported by the nondetection of H2 in non-Mira stars, S stars, and carbon stars. The possibility that the observed apparent hydrogen deficiency has resulted from a mass loss process is considered. Observations indicate that TP-AGB stars become hydrogen deficient before the Mira phase.
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    The Broad Band X-ray telescope (1985)
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    Publication Date: 2011-08-19
    Description: The Broad-Band X-ray Telescope (BBXRT) has been designed to perform high sensitivity, moderate resolution spectrophotometry of X-ray sources in the 0.3-12 keV band from the Shuttle. It consists of a coaligned pair of high throughput conical X-ray imaging mirrors, with a cryogenically cooled multiple element Si(Li) spectrometer at the focus of each. On axis, BBXRT will have an effective area of 580 sq cm at 2 keV and 250 sq cm at 7 keV, and a spectral resolution of 110 eV at 2 keV and 150 eV at 7 keV. A 10,000-s observation with BBXRT will allow a determination of the continuum spectral shape for sources near the Einstein deep survey limit.
    Keywords: ASTRONOMY
    Type: Space Science Reviews (ISSN 0038-6308); 40; 707-713
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    Spectral constraints on models of gas in clusters of galaxies (1985)
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    Publication Date: 2011-08-19
    Description: The HEAO 1A2 spectra of clusters of galaxies are used to determine the temperature profile which characterizes the X-ray emitting gas. Strong evidence of nonisothermality is found for the Coma, A85, and A1795 clusters. Properties of the cluster potential which binds the gas are calculated for a range of model parameters. The typical binding mass, if the gas is adiabatic, is 2-4E14 solar masses and is quite centrally concentrated. In addition, the Fe abundance in Coma is .26 + or - .06 solar, less than the typical value (.5) found for rich clusters. The results for the gas in Coma may imply a physical description of the cluster which is quite different from what was previously believed.
    Keywords: ASTROPHYSICS
    Type: Space Science Reviews (ISSN 0038-6308); 40; 681-688
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    H0323+022 - Classification as a BL Lac and EXOSAT coordinated observations (1985)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: The object H0323+022 (Doxsey et al. 1983) has been shown to be a BL Lac object by virtue of a diversity of observational characteristics at radio, optical, and X-ray wavelengths, in agreement with the conclusion of Margon and Jacoby (1984). Multi-frequency coordinated observations of this highly variable object with EXOSAT in September 1984 found it to be in a faint quiescent state (approximately 1/3 micron-Jy at approximately 5 keV and V = 16.55). Preliminary results from the latter observations are presented.
    Keywords: ASTROPHYSICS
    Type: Space Science Reviews (ISSN 0038-6308); 40; 613-617
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    The discovery of a 25 min regular modulation in the X-ray flux from 2S0142 + 61 (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A 13 hr observation of 2S0142 + 61 on August 27, 1984 by EXOSAT shows the X-ray flux of 2S0142 + 61 to be modulated with a period of 1456+/-6 s. The 1-10 keV spectrum is two component with an approximately 0.7 keV thermal and 0.0 energy index power law, with 30 percent of the total luminosity in the thermal component. The spectrum is absorbed by about 1 x 10 to the 22nd H per sq cm. Only the hard component is pulsed with a 3 to 10 keV peak to mean amplitude of 35 percent. Below 2 keV the modulation is less than a few percent. The total 1-10 keV luminosity is 3.5 x 10 to the 32nd erg/s for a distance of 100 pc. Possible optical counterparts are discussed.
    Keywords: ASTROPHYSICS
    Type: Space Science Reviews (ISSN 0038-6308); 40; 157-162
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  • 62
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    The determination of physical and dynamical parameters of Pluto/Charon and binary asteroids by least-square formation of a matched filter for a time series of images. I - The operational theory (1985)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Description: A theory is derived for the determination of the masses, radii, and orbital elements of the Pluto/Charon, or similar, system based on the prediction of an image distribution over space and time and its comparison with observation. The comparison may be ultimately through the theory of least squares or the application of a matched filter to the observations as a three-dimensional signal stream at an initial or intermediate state. The theory is an approximation correct to fifth order in the diameters of celestial bodies. The theory of astronomical seeing that is used is based on Kolmogorov turbulence in the long-exposure limit. The images must be photometric. Linear tracking errors that can be removed are preferable to either automatic or manual guiding, in the collection of candidate observations.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 90; 1883-189
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  • 63
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    A VLBI survey at 2.29 GHz (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: VLBI observations at 2.29 GHz with fringe spacings of about 3 milliarcsec have been performed on 1398 radio sources spread over the entire sky. 917 sources were detected, including 93 percent of the identified BL Lacertae objects, 86 percent of the quasars, and 36 percent of the galaxies. The resulting catalog of compact radio sources is useful for various astrophysical studies and in the formation of VLBI celestial reference frames.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 90; 1599-164
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  • 64
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    Modeling the effects of latitudinal gradients in stellar winds, with application to the solar wind (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A steady, axisymmetric, quasi-radial, global model previously developed for stellar winds with embedded magnetic fields has been extended to include latitudinal gradient effects on the azimuthal velocity and magnetic field. The linear results at large radii are presented for large-amplitude latitudinal variations in the radial magnetic field, mass loss rate, and radial velocity of the wind. The magnetohydrodynamic (MHD) equations predict meridional flows that develop naturally from internal magnetic stresses. The flows open flux tubes in the star's equatorial plane, redistributing mass and magnetic flux as a function of stellar latitude. The plasma spins up to conserve angular momentum in fields and plasma. The results are generally applicable to stellar winds (including radiatively driven winds), provided that the internal structure is not dominated by rotation. The asymptotic solutions do not explicitly depend on the form of the energy equation, although the assumed O(1) state which drives these solutions depends on the deposition of energy and momentum throughout the wind.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 296; 259-267
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  • 65
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    An interpretation of the spectral variations of Theta Coronae Borealis (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Measurements are presented of the strengths and displacements of sharp absorption components of the resonance lines of Si IV, C IV, and Al III in the spectrum of Theta CrB. No evidence is found for mass loss at a detectable rate. A qualitative model of a Be star is developed. It is suggested that the spectral variations of Theta CrB are the result of changes in the rate at which magnetic flux is generated in the envelope of the star and extruded through the photosphere of the star.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics (ISSN 0004-6361); 148; 2, Ju
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  • 66
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    Black hole accretion disks - Electrodynamic coupling of accretion-disk coronae and the partitioning of soft and hard X-ray emission (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: It is demonstrated that the observed large ratio of hard to soft X-ray emission and the bimodel behavior of black hole accreting X-ray sources such as Cygnus X-1 can be described in terms of a magnetically structured accretion disk corona which is electrodynamically coupled to the disk turbulent motions while the disk is thermodynamically coupled to the corona as described by a feedback parameter delta. The observed ratio of hard to soft X-ray emission is independent of the disk thickness, and weakly dependent of the disk parameter alpha relating the disk viscous stresses to the total pressure. Observed values of the luminosity ratio point towards strong differences of the feedback of the low state compared to the high state, in the sense that low state means small feedback (delta less than 0.2) and high state means strong feedback delta of about 0.5.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics (ISSN 0004-6361); 148; 2, Ju; 309-311
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  • 67
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    Light variations of Periodic Comet Halley beyond 7 AU (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The present examination of brightness data on the Periodic Comet Halley over the October 1982-February 1984 period, for evidence concerning nucleus rotation period and projected cross section area, notes variations of up to 5:1 in intrinsic brightness. Application of a period-determination technique has failed to yield a clear choice for the true rotation period among a large number of peaks in the spectrum, some of which virtually coincide with the sun's rotation period and its submultiples. It is found that rotation periods longer than about 1 day are the most likely; it is suggested that the observed light curve is a composition of periodic and erratic variations.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics (ISSN 0004-6361); 148; 2, Ju; 299-308
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  • 68
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    Soft X-ray spectral observations of low-luminosity active galaxies (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The X-ray spectra of a sample of 12 low-luminosity AGNs observed using the solid state spectrometer on the HEAO 2 satellite are investigated. The AGNs discussed here have X-ray luminosities below about 10 to the 44th erg/s, and thus form a sample complementary to the higher luminosity sample discussed by Petre et al. (1984). The spectra are well described by a simple model consisting of a power law, with photon spectral index about 1.7, plus absorption by cold gas. The objects in the sample can be separated into three groups: (1) those whose spectra show no significant absorption; (2) those for which the X-ray source is totally covered by a spatially uniform absorbing medium; and (3) those for which partial covering by 'patchy' absorbers is indicated. Column densities and covered fractions do not correlate systematically with X-ray luminosity. Implications regarding physical conditions in AGNs are discussed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 296; 69-89
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  • 69
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    The brightest high-latitude 12-micron IRAS sources (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The Infrared Astronomical Satellite (IRAS) Point Source catalog was searched for sources brighter than 28 Jy (0 mag) at 12 microns with absolute galactic latitude greater than 30 deg excluding the Large Magellanic Cloud. The search resulted in 269 sources, two of which are the galaxies NGC 1068 and M82. The remaining 267 sources are identified with, or have infrared color indices consistent with late-type stars some of which show evidence of circumstellar dust shells. Seven sources are previously uncataloged stars. K and M stars without circumstellar dust shells, M stars with circumstellar dust shells, and carbon stars occupy well-defined regions of infrared color-color diagrams.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific, Publications (ISSN 0004-6280); 97; 616-633
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  • 70
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    A new luminosity component in 3C 48 (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The infrared emission from the quasar 3C48 has a luminosity L approximately 5 x 10 to the 12th power solar luminosity and dominates the power output of the quasar system. It is shown that the infrared emission, unlike that of most radio loud quasars, is most likely not an extension of the radio emission of the quasar. It is argued that the infrared emission in 3C48 is probably thermal radiation arising in a highly luminous galaxy surrounding the quasar.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X); 295; L27-L31
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  • 71
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    VLBI observations of the jet in Cygnus A (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The luminous radio galaxy Cyg A was observed with a five-station US VLBI array at 5 GHz at epoch 1983.25. The jet can be followed from the core to a distance of 9 milliarcsec (mas). Within the limited dynamic range of these observations, it is one-sided (jet:counterjet ratio greater than 12:1). If this one-sidedness is due to Doppler boosting, then (1) the jet must decelerate to a mildly relativistic velocity on a kiloparsec scale, (2) the source cannot lie with 30 deg of the plane of the sky. The jet points directly at the base of the kpc-scale jet seen by Perley, Dreher, and Cowan (1984); the curvature occurs primarily or entirely on a scale of 10-100 kpc. The jet brightness falls off more slowly inside 1 kpc than in other powerful sources. A search for compact structure in the three bright hot spots revealed no structure lower than 3 mas in size with flux greater than 6 mJy.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 295; 463-465
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  • 72
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    On the trail of Comet G-Z (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The International Cometary Explorer (ICE) is to investigate the magnetic and electric fields, plasmas, and particles in the Comet Giacobini-Zinner (G-Z) and to study its interaction with solar wind. The ICE can pass through the comet only once and it will take 90 minutes to cross from one side of the tail to the other. Since the Comet G-Z often changes its orbit due to nongravitational forces changing its direction and velocity, ICE's position needs to be adjusted. The probe is aimed 10,000 km from the nucleus in order to be provided the best passage through the Comet G-Z. The 64-meter dishes of JPL's Deep-Space Network (DSN) will receive data transmitted on two adjacent S-band frequencies at the rate of 1024 bits per second. Also NASA has arranged for the radio telescope at Arecibo to record the transmission. The Japanese 64-meter tracking antenna at Usada, equipped with an ultrasensitive receiver for one ICE frequency, will provide pre-encounter and post-encounter tracking. The ICE data may provide information about the dust tail in the Comet G-Z which could be compared to previous research.
    Keywords: ASTRONOMY
    Type: Sky and Telescope (ISSN 0037-6604); 70; 198-203
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  • 73
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    The C-12/C-13 isotope ratio toward Zeta Ophiuchi (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Observations of interstellar CH(+) toward Zeta Oph were performed to determine the C-12/C-13 isotope ratio in this diffuse cloud. The very high signal-to-noise ratio spectra yield 6 sigma detections of the (C-13)H(+) features at 4232 A and 3957 A; a weighted mean C-12/C-13 ratio of 43 + or - 6 (1 sigma) is obtained. The uncertainty includes the contribution of continuum placement errors, statistical channel-to-channel signal fluctuations, and the error introduced in deconvolving the blended isotopic lines at 4232 A. This result indicates a decrease in the local galactic C-12/C-13 ratio by a factor of 2 during the 4.6 billion yr since the formation of the sun.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X); 294; L131-L13
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  • 74
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    An optical measurement of the population inversion of the ground state Lambda doublet of interstellar CH (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 294; 238-241
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  • 75
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    Seyfert galaxy narrow-line regions. II - Kinematic models (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A class of kinematic models for the narrow-line regions of active galactic nuclei is presented. The models incorporate continuity-constrained radial flow of emitting material in a bounded, spherical geometry. They are designed to represent the narrow-line regions in as simple a manner as is consistent with current knowledge. The systematic comparison of line profiles arising from the models to the spectra in the forbidden O III lambda 5007 emission line which have been described in Paper I of this series is used as a probe of the line-emitting region kinematics: the model parameter areas of interest are identified and tested for consistency with the data. The results indicate heterogeneous kinematic conditions; the most common pattern is outflow of emitting material in a radially decelerating velocity field in the presence of distributed obscuration. However, some observed line profiles can be fitted by several model profiles from very different kinematic conditions, indicating that the information in a spatially unresolved line profile is insufficient to constrain uniquely the geometry and kinematics of the line-emitting region. Although the specific conclusions are model dependent, a predominantly radial pattern of velocities and a distribution of obscuring material are probably essential features of any successful kinematic model of the narrow-line regions.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 294; 121-133
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  • 76
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    The gamma-ray spectrum of the Galactic center region (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The Galactic center region was observed with the HEAO 3 High Resolution Gamma-Ray Spectrometer during the fall of 1979 and the spring of 1980. Between these epochs there was observed (1) a statistically significant decrease in the high-energy (511 keV to about 3 MeV) luminosity, (2) a decrease in the positron annihilation line intensity, reported previousy, and (3) a low positronium annihilation fraction f = 0.38 + or 0.19 during the fall of 1979. If positrons are generated by photon-photon collisions of high-energy photons, then the absence of a detected flux above 511 keV in the spring of 1980 may indicate a time delay between positron production and annihilation.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X); 294; L13-L15
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  • 77
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    A large, cold, and unusual molecular cloud in Monoceros (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Observations of the J = 1 tends to 0 rotational transition of CO near the galactic plane in Monoceros (1 is approximately equal to 216 deg) reveal a molecular cloud with unusually low peak CO temperatures (less than 2 K) but wide lines (about 7 km/s) typical of much warmer clouds. At the assumed distance of 3 kpc, the cloud is large (250 x 100 pc), has a mass of 7-11 x 10 to the 5th solar masses, and is well removed from the galactic midplane (130 pc). Except for a possible H II region, all the signs of star formation usually shown by clouds of comparable mass are missing. The cloud, unlike cloud complexes of similar size, is a single, continuous object that apparently has not been torn apart by star formation. Clouds with such properties are rare in the Galaxy; only one or two similar objects have been found. The possibility that the cloud is young and not yet forming stars but will evolve into a typical cloud complex once star formation begins is discussed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 294; 231-237
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  • 78
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    Astronomical identification of the C3H radical (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The C3H radical has been identified in the millimeter-wave spectra of IRC +10216 and TMC-1. In IRC +10216, four rotational transitions have been observed, three in the lower fine-structure ladder (2Pi1/2) and one in the upper (2Pi3/2), each a resolved or partially resolved lambda-doublet. In TMC-1, both lambda components of the lowest lying 3/2-1/2 transition of the 2Pi1/2 ladder have been observed, each with well-resolved hfs. In IRC +10216, the excitation of C3H is similar to that of SiCC: the rotational temperature Trot within the 2Pi1/2 ladder is low (8.5 K), because of rapid radiative decay, while Trot across the ladders is high (about 52 K), because interconnecting far-IR radiative transitions are only weakly permitted. The column density of C3H in IRC +10216 averaged over the estimated source diameter of 84 arcsec is 2.8 x 10 to the 13th/sq cm, an order of magnitude less than that of C2H and C4H.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X); 294; L49-L53
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  • 79
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    Laboratory detection of the C3H radical (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Millimeter-wave lines of the C3H radical, including six of the lines observed in space, were detected in a laboratory glow discharge through a flowing mixture of C2H2, He, and CO. Each of the 10 rotational transitions measured, five between 98 and 185 GHz in the 2Pi1/2 ladder and five between 80 and 194 GHz in the 2Pi3/2 ladder, is split by lambda-type doubling, and all but three possess resolved hyperfine structure. The excellent agreement between the fine-structure, rotation, lambda-doubling, and hyperfine constants derived from the laboratory data and from the astronomical observations conclusively confirms the identifications in IRC +10216 and TMC-1 by Thaddeus and colleagues (1985). An accurate set of spectroscopic constants, which allow calculation of the entire radio spectrum of C3H to a radial velocity of 0.1 km/s, was derived from a simulataneous fit to the laboratory frequencies and to the well-resolved hfs observed in the narrow-line astronomical source TMC-1.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X); 294; L55-L58
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  • 80
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    Detection of interstellar CCD (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The first detection of interstellar CCD has been obtained in the N = 3-2, J = 7/2-5/2 line at 216.3732 GHz towards the Kleinman-Low nebula. An abundance ratio CCD/CCH of 0.045 is found, indicating in this molecule a deuterium enhancement similar to that found for HNC, but an order of magnitude higher than for HCN. Negative results towards DR 21(OH), NGC 2264, L 134N, TM Cl, Rho OphB2, and IRC 10216 rule out a stronger D enhancement for CCD than for other deuterated molecules in these sources. Predictions of currently developed ion-molecule reaction schemes are consistent with the CCD line detected and the negative results.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics (ISSN 0004-6361); 147; 2, Ju; L25
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  • 81
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    Spectroscopy of the 3 micron emission features (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: High-spectral-resolution observations of the 3.3 and 3.4 microns features in the three planetary nebulae NGC 7027, IC 418, and BD +30 deg 3639, in the H II region S106, and in the 'red rectangle' HD 44179 are presented. The profile of the unidentified 3.3 microns emission feature is similar in all five sources. The unidentified feature previously referred to as the 3.4 microns feature actually consists of two components, a low-level emission from 3.35 to 3.60 microns and a narrow emission peak at 3.40 microns. The strength of the latter feature relative to that of the 3.3 microns feature varies by a a factor of three from source to source. The origin and properties of these features may be explained by further development of the small-grain models of Sellgren (1984) and Leger and Puget (1984).
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 292; 500-505
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  • 82
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    Dynamical activity in V1016 Cygni (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: New high-dispersion IUE observations show the C IV emission lines in V1016 Cygni to be split, suggesting evidence for dynamical activity. The Mg V line shows structure nearly identical to the C IV lines when plotted in velocity space.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 2 - Letters to the Editor (ISSN 0004-637X); 292; L15-L18
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  • 83
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    X-ray emission from Be star binaries (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A model in which a neutron star in an eccentric inclined orbit around a Be star passes through a ring of matter around the Be star has been used to explain the recurrent flares of X-ray emission from these systems. The optical emission during X-ray flares is due to partial absorption and reprocessing of the X-rays in the ring.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 292; 257-259
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  • 84
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    Stellar evolution at high mass with convective core overshooting (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The transition from stellar evolution models with no convective core overshooting (CCO) at all to models in which homogeneous mixing due to CCO reaches far beyond the formal convective core boundary is systematically explored. Overshooting is parameterized in terms of the ratio d/H(p), where d is the distance of convective overshoot beyond the formal convective core boundary and H(p) is the local pressure scale height. It is concluded that CCO in very massive main sequence stars produces a great expansion of the stellar envelope if d/H(p) is large but not excessively large. CCO does not entirely suppress convective instability above the overshoot zone in the envelopes of main sequence stars more massive than about 15 solar masses. A general comparison of theoretically constructed isochrones for young stars with observed main sequence turnups indicates that the observed turnups are longer, brighter, and cooler at the tip than those expected on thfe basis of standard evolutionary theory.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 292; 222-227
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  • 85
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    Optical and infrared pulsations from the HZ Herculis binary system during the 1983 prolonged X-ray low state (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Pulsed infrared and optical flux from HZ Her has been detected during the 1983 prolonged X-ray low state by simultaneous observations with the Lick Observatory Shane 3.1 m and Crossley 91 cm telescopes. The pulsed fluxes in the 1.0-2.5-micron bandpass and the 3200-7500 A bandpass agree in pulse frequency and phase and were measured to be 31 and 13 microJy, respectively. These pulsed fluxes indicate that the reprocessed pulsation spectrum is consistent with optically thin thermal bremsstrahlung radiation with a characteristic temperature of 25,000 K (+25,000; -12,500) which is modulated in intensity. An apparent earth-approaching Doppler velocity of about 65 km/s is observed for these pulsed fluxes; this velocity can be interpreted as pulsed X-ray reprocessing by material in the mass transfer stream between L1 and the outer edge of the accretion disk. Other optical observations made during and before the 1983 prolonged X-ray low state show that the optical pulsations may have been subtly affected by the obscuration responsible for the X-ray low.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 292; 267-275
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  • 86
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    Consequences of hot gas in the broad-line region of active galactic nuclei (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Models for hot gas in the broad line region of active galactic nuclei are discussed. The results of the two phase equilibrium models for confinement of broad line clouds by Compton heated gas are used to show that high luminosity quasars are expected to show Fe XXVI L alpha line absorption which will be observed with spectrometers such as those planned for the future X-ray spectroscopy experiments. Two phase equilibrium models also predict that the gas in the broad line clouds and the confining medium may be Compton thick. It is shown that the combined effects of Comptonization and photoabsorption can suppress both the broad emission lines and X-rays in the Einstein and HEAO-1 energy bands. The observed properties of such Compton thick active galaxies are expected to be similar to those of Seyfert 2 nuclei. The implications for polarization and variability are also discussed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 292; 49-57
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  • 87
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    Recent heavy-particle decay in a matter-dominated universe (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The cold matter scenario for galaxy formation solves the dark matter problem very nicely on small scales corresponding to galaxies and clusters of galaxies. It is, however, difficult to reconcile with a Universe with an Einstein-deSitter value of (UC OMEGA) = 1. Cold matter and (UC OMEGA) = 1 can be made compatible while retaining the feature that the Universe is matter dominated today. This is done by means of heavy (cold) particles whose decay subsequently leads to the unbinding of a large fraction of lighter clustered matter.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 292; 1-11
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  • 88
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    Periodic orbits of the general three-body problem for the sun-Jupiter-Saturn system (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Two families of symmetric periodic orbits of the planar, general, three-body problem are presented. The masses of the three bodies include ratios equal to the sun-Jupiter-Saturn system and the periods of the orbits of Jupiter and Saturn are in a 2:5 resonance. The (linear) stability of the orbits are studied in relation to eccentricity and mass variations. The generation of the two families of periodic orbits follows a systematic approach and employs (numerical) continuation from periodic orbits of the first and second kind in the circular restricted problem to the elliptic restricted problem and from the circular and elliptic problems to the general problem through bifurcation phenomena relating the three dynamical systems. The approach also provides insight into the evolutionary process of periodic orbits continued from the restricted problems to the general problem.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics (ISSN 0008-8714); 35; 289-303
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  • 89
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    Durability of the accretion disk of millisecond pulsars (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Pulsars with pulsation periods in the millisecond range are thought to be neutron stars that have acquired an extraordinarily short spin period through the accretion of stellar material spiraling down onto the neutron star from a nearby companion. Nearly all the angular momentum and most of the mass of the companion star is transferred to the neutron star. During this process, wherein the neutron star consumes its companion, it is required that a disk of stellar material be formed around the neutron star. In conventional models it is supposed that the disk is somehow lost when the accretion phase is finished, so that only the rapidly spinning neutron star remains. However, it is possible that, after the accretion phase, a residual disk remains in stable orbit around the neutron star. The end result of such an accretion process is an object that looks much like a miniature (about 100 kilometers), heavy version of Saturn: a central object (the neutron star) surrounded by a durable disk.
    Keywords: ASTROPHYSICS
    Type: Science (ISSN 0036-8075); 228; 1015
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  • 90
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    Time-resolved UV spectroscopy of BE Ursae Majoris (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Far-ultraviolet spectra have been obtained of the eclipsing, hot subdwarf binary, BE UMa, with phase coverage in the 2.3-day orbital period concentrated near minimum light. No clearly phase-related spectra changes were found, but the UV continuum appeared to be in a highly variable state, with changes of a factor of two occurring on a time scale of hours. The hot star in this system may be one of the few known PG1159-035 variables, which show nonradial pulsations. If so, this is the first such star known in a binary system and thus should be important for determining the physical properties of these stars.
    Keywords: ASTROPHYSICS
    Type: Astronomical Society of the Pacific, Publications (ISSN 0004-6280); 97; 328-332
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  • 91
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    Submilliarcsecond VLBI observations of the close pair GC 1342 + 662 and GC 1342 + 663 (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Differential VLBI was simultaneously performed on the source pair GC 1342 + 662 and GC 1342 + 663 (4.4-arcminute separation) using S-band on the Goldstone/Madrid baseline. These measurements were acquired on two separate observing sessions: 30 December 1982 and 14 May 1983. The change in separation of GC 1342 + 662 relative to GC 1342 + 663 between the two epochs was 0.03 + or - 0.08 milliarcsecond. The differences of the relative position measurements between epochs of GC 1342 + 662 relative to GC 1342 + 663 were -0.29 + or - 0.05 milliarcsecond in right ascension and 0.14 + or 0.09 milliarcsecond in declination. These measurements demonstrate submilliarcsecond accuracy and repeatability. The discrepancies outside of the formal uncertainties could be attributed to the intrinsic properties of the sources such as structure and to a lesser probability, proper motion. These discrepancies could also be attributed to excursions in UT1-UTC of about four times the quoted BIH uncertainty.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 90; 1004-100
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  • 92
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    Are galaxies more strongly correlated than clusters? (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Distributions of galaxies and of clusters of galaxies have been investigated using the correlation function, the excess probability over random that there are two objects separated by a distance r. It is shown here that if the amplitudes of the cluster-cluster correlation function are made dimensionless, systematic changes with cluster richness vanish, implying scale invariance in the cluster process. The dimensionless galaxy-galaxy correlation seems stronger, implying gravitational enhancement on smaller scales.
    Keywords: ASTROPHYSICS
    Type: Nature (ISSN 0028-0836); 314; 718
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  • 93
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    Theoretical interpretation of the observed interplanetary magnetic field radial variation in the outer solar system (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Observations of the azimuthal component of the IMF are evaluated through the use of an MHD model which shows the effect of magnetic flux tubes opening in the outer solar system. It is demonstrated that the inferred meridional transport of magnetic flux is consistent with predictions by the MHD model. The computed azimuthal and radial magnetic flux deficits are almost identical to the observations. It is suggested that the simplest interpretation of the observations is that meridional flows are created by a direct body force on the plasma. This is consistent with the analytic model of Nerney and Suess (1975), in which such flux deficits in the IMF arise naturally from the meridional gradient in the spiralling field.
    Keywords: ASTROPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 90; 4378-438
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  • 94
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    A finding list for the multiplet tables of NSRDS-NBS3, Sections 1-10 (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The preparation of a magnetic-tape finding list for the first 10 sections of the U.S. National Bureau of Standards Reference Data System (NSRDS-NBS3) tables of optical multiplets of astrophysical interest (Moore, 1965-1983) is reported. The format of the list is described, and a sample page is provided.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics Supplement Series (ISSN 0365-0138); 60; 339-341
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  • 95
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    A transformation of the two-body problem (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A transformation of the differential equations of motion of the two-body problem in the spherical coordinates to oscillator form is derived. It is shown that the independent variable transformation dt/ds = r squared is a transformation which makes the oscillator form possible.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics (ISSN 0008-8714); 35; 1-7
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  • 96
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    Epsilon Aurigae (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: In April 1984, fourth contact ended the two year long eclipse of Epsilon Aurigae. An astrometric study of the study of the system was carried out by Van de kamp (1978) leading to the conclusion that the orbit is seen very close to edge on. The eclipse was monitored by a number of groups from the ground and from spacecraft such as the IUE. Ultraviolet observations of the system from IUE have thrown new light on the nature of the system that led to the conclusion that the secondary object is probably a cold, dusty accretion disk surrounding a star that is completely hidden inside the disk.
    Keywords: ASTRONOMY
    Type: Astrophysics and Space Science (ISSN 0004-640X); 110; 1, Ma
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  • 97
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    Absolute calibration of photometry at 1 through 5 microns (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: The solar-analog method is used to determine the absolute calibration of photometry in the J, H, K, L, and M bands to an accuracy of 3 percent, (5 percent at M). This calibration agrees well with the direct calibration obtained by Blackwell et al. (1983); this agreement gives confidence that the calibration is known to an accuracy of 2 percent to 3 percent. The agreement also implies that the behavior of solar type stars is well understood in the infrared and that such stars make reliable standards for calibration of nonstandard photometric bands and for planetary reflectance studies. Both methods indicate that Vega is slightly brighter than indicated by atmospheric models.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 90; 896-899
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  • 98
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    An absolute photometric system at 10 and 20 microns (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Two new direct calibrations at 10 and 20 microns are presented in which terrestrial flux standards are referred to infrared standard stars. These measurements give both good agreement and higher accuracy when compared with previous direct calibrations. As a result, the absolute calibrations at 10 and 20 microns have now been determined with accuracies of 3 and 8 percent, respectively. A variety of absolute calibrations based on extrapolation of stellar spectra from the visible to 10 microns are reviewed. Current atmospheric models of A-type stars underestimate their fluxes by about 10 percent at 10 microns, whereas models of solar-type stars agree well with the direct calibrations. The calibration at 20 microns can probably be determined to about 5 percent by extrapolation from the more accurate result at 10 microns. The photometric system at 10 and 20 microns is updated to reflect the new absolute calibration, to base its zero point directly on the colors of A0 stars, and to improve the accuracy in the comparison of the standard stars.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 90; 900-906
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  • 99
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    Surface photometry of comet P/Encke (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: A scheme to clean cometary digital images from offending background-star trails, and this technique has been applied to a pair of deep Kitt Peak 4-m plates of comet P/Encke, taken in October 1980. Simultaneous and subsequent digital spectra have been obtained at Lick Observatory. The non-polluted coma images show a strong asymmetric sunward-oriented fan/jet, and an extended and rounder (mostly gaseous) main coma, out to approximately 100,000 km radius. The stellar-trail point-spread function has a narrow width (sigma approximately 0.6 arcsec), so that spatial resolution better than approximately 300 km is achieved at the comet. The photometric gradient near the nucleus is very steep, strongly suggesting an icy-grain component which evaporates quickly (at radii equal to or less than 500 km) in the sunlight. Further from the nucleus, the profile becomes shallower, bluer, and more gas dominated. The effect of solar radiation pressure on C2, CN, and other molecules is probably responsible for the rounding of the outer, fainter isophotes. The source of the molecules is likely to be larger than the nucleus itself, and a substantial fraction may originate in the jet. The technique described here may also be applicable in surface photometry of galaxies, in cases where the heavy image pollution by foreground stars is present.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 90; 869-876
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  • 100
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    Coma morphology and dust-emission pattern of periodic comet Halley. III - Additional high-resolution images taken in 1910 (1985)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: High-resolution photographic images of comet Halley obtained at Lick, Helwan, Lowell, and Vienna observatories during May-June 1910 are analyzed using the image-processing algorithm of Larson and Sekanina (1984). The results are presented in tables and compared with analyses of Mt. Wilson plates for the same period (Sekanina and Larson, 1984), and good general agreement is noted. Consideration is given to the position of the rotation pole, features indicative of the nucleus spin rate, the spokelike structure observed on May 21-22, and the expanding gas halo.
    Keywords: ASTROPHYSICS
    Type: Astronomical Journal (ISSN 0004-6256); 90; 823-826
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