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  • ASTROPHYSICS  (546)
  • 1980-1984  (546)
  • 1925-1929
  • 1982  (546)
  • 1
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    Kinetic theory in astrophysics and cosmology (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Results associated with exact solution of the Einstein-Boltzmann and Einstein-Maxwell-Boltzmann equations are presented. The generalization of Ehler's killing vector approach for the distribution function to charged particles is considered.
    Keywords: ASTROPHYSICS
    Type: Alabama Univ. in Huntsville The 1981 NASA(ASEE Summer Fac. Fellowship Program; 21 p
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  • 2
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    The Crab Nebula's progenitor (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The initial mass of the Crab Nebula's progenitor star is estimated by comparing the observed nebular chemical abundances with detailed evolutionary calculations for 2.4- and 2.6-solar-mass helium cores of stars with masses of 8 to 10 solar masses. The results indicate that the mass of the Crab's progenitor was between the upper limit of about 8 solar masses for carbon deflagration and the lower limit of about 9.5 solar masses set by the dredge-up of the helium layer before the development of the helium-burning convective region. A scenario is outlined for the evolution of the progenitor star. It is suggested that the Crab Nebula was probably the product of an electron-capture supernova.
    Keywords: ASTROPHYSICS
    Type: Nature; 299; Oct. 28
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  • 3
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    Cosmic turbulence and the angular momenta of astronomical systems (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: It is suggested that gravitationally bound astronomical systems ranging from asteroids to galaxy superclusters may derive their rotation from a hierarchy of cosmic turbulence, thus explaining the empirical specific angular momentum-mass relationship (j approximately equal to M to the 3/4 power) exhibited by these systems. It is shown that many of the properties of these systems, e.g., the random orientation of their spin vectors, can be accounted for if astronomical objects form in a turbulent environment.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 261
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  • 4
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    Relativistic kinematics for motions faster than light (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-20197)
    Keywords: ASTROPHYSICS
    Type: vol. 35; Nov. 198
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  • 5
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    Water as a probe of star-forming regions (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Preliminary calculations employing statistical equilibrium techniques were carried out to determine brightness temperatures of water transitions occurring in the submillimeter band. The interesting candidates appear to be the 325 GHz, 380 GHz, and 448 GHz transitions, they are compared with the 183 GHz and 380 GHz transitions observed in the Orion Kleinmann-Low nebula and the combined results seem to be consistent with H2 densities of 100,000 -1 million cm-3 and a water column density of approximately 10 to 18th power. This implies a relative abundance of approximately 0.00001 which means that water may be about one twentieth of CO. In addition, it was found that for the conditions of the Orion plateau source, the 448 GHz line is expected to be a mild maser.
    Keywords: ASTROPHYSICS
    Type: ESA The Sci. Importance of Submillimetre Observations; p 129-130
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  • 6
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    Radiation from the accretion column of magnetized neutron stars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Some developments in radiative transfer for magnetized neutron star conditions, and their application in models of the structure and properties of self-consistent polar cap emission regions are reviewed. Several of the assumptions and uncertainties involved are discussed, and present problems are indicated.
    Keywords: ASTROPHYSICS
    Type: Max-Planck Inst. Phys. and Astrophys. Accreting Neutron Stars; p 253-274
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  • 7
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    Spectral evolution of active galactic nuclei - A unified description of the X-ray and gamma-ray backgrounds (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-22137)
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 260
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  • 8
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    On OMC-1 temperatures determined from methyl cyanide observations (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An analysis is performed on the J(k) = 12(k)-11(k) and 13(k)-12(k) transitions of methyl cyanide detected by other investigators in the direction of OMC-1. The original interpretation of those observations argues for the presence of two distinct temperature regions or possibly a temperature gradient within the cloud. The analysis presented here demonstrates that the observations of these particular molecular transitions are consistent with a single methyl cyanide emission region with a source kinetic temperature of 121.2 + or - 8.2 K and a molecular rotational temperature of 16.6 + or - 1.8 K.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 260
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  • 9
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    A large scale height galactic component of the diffuse 2-60 keV background (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The diffuse 2-60 keV X-ray background has a galactic component clearly detectable by its strong variation with both galactic latitude and longitude. This galactic component is typically 10 percent of the extragalactic background toward the galactic center, half that strong toward the anticenter, and extrapolated to a few percent of the extragalactic background toward the galactic poles. It is acceptably modeled by a finite radius emission disk with a scale height of several kiloparsecs. The averaged galactic spectrum is best fitted by a thermal spectrum of kT about 9 keV, a spectrum much softer than the about 40 keV spectrum of the extragalactic component. The most likely source of this emission is low luminosity stars with large scale heights such as subdwarfs. Inverse Compton emission from GeV electrons on the microwave background contributes only a fraction of the galactic component unless the local cosmic ray electron spectrum and intensity are atypical.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 260
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  • 10
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    BL Herculis stars - Theoretical models for field variables (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Type II Cepheids with periods between 1 and 3 days, commonly designated as Bl Herculis stars, have been modeled here with the aim of interpreting the wide variety of light curves observed among the field variables. Previously modeled globular cluster members are used as standard calibration objects. The major finding is that only a small range of luminosities is capable of generating a large variety of light curve types at a given period. For a mass of approximately 0.60 solar mass, the models are able to reproduce the observed mean luminosities, dispersion of mean luminosities, periods, light amplitudes, light asymmetries, and phases of secondary features in the light curves of known BL Her stars. It is possible that the metal-rich variables (which are found only in the field) have luminosities lower than those of most metal-poor variables. The present revised mass for BL Her, a metal-rich object, is not significantly different from the mean mass of the metal-poor variables.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 259
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  • 11
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    A heuristic criterion for instability to fragmentation in rotating, interstellar clouds (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A heuristic criterion, based on linear perturbation analysis, is applied to the initial growth of density perturbations in isothermal or adiabatic gas clouds, with initially uniform density and uniform rotation. The heuristic criterion is shown to be consistent with the available results from numerical calculations of cloud collapse. The criterion predicts that perturbations varying as cos(m-phi) will be most likely to grow when m is small, unless the cloud is nearly pressureless.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 259
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  • 12
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    High energy X-ray observations of Cyg X-3 from OSO-8 - Further evidence of a 34.1 day period (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-18085)
    Keywords: ASTROPHYSICS
    Type: Astrophysical Letters; 22; 4, 19; 1982
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  • 13
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    Neutron star collisions and the r-process (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: It is shown that a natural consequence of the binary pulsar's evolution is a neutron star collision. Such a collision is expected to eject neutron-rich matter of an r-process character. Taking reasonable estimates for the number of such events over the history of the galaxy, it may be that they account for all of the r-process nuclei.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Letters; 22; 4, 19; 1982
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  • 14
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    The peculiar variable star R Aquarii and its jet (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Observations of the variable star R Aquarii from 1928 to the present are examined to conclude that the star is a binary system with a jet. The orbital period of the objects is estimated at 22 yr, and a supercritical mass transfer that occurs once every 44 yr is suggested as a mechanism to explain deep minima observed on two occasions that many years apart. Calculations presented for the critical accretion rate of the two Miras indicated that one of the objects possesses a substantially stronger gravitational field than the other and features a large accretion disk. Oriental astronomical records from 930 AD are cited as evidence that a nova occurred in the vicinity of R Aquarii at that time. The system is noted to be the closest jet thus far observed, and the accretion disk may be visible with the Space Telescope.
    Keywords: ASTROPHYSICS
    Type: Nature; 298; Aug. 5
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  • 15
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    The photospheric velocity field of Procyon (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Balloon-borne Ultraviolet Stellar Spectrometer observations of the profiles of two well observed spectral lines in the ultraviolet spectrum of Alpha CMI (Procyon; F5IV-V) are analyzed with a Fourier transform method in order to determine values of various parameters of the velocity field of the upper photosphere. A microturbulent line-of-sight velocity component of 0.9 + or - 0.4 km/s, a macroturbulent velocity component of 5.3 + or - 0.2 km/s, and a rotational velocity component of 10.0 + or - 1.2 km/s were determined. In these calculations a single-moded sinusoidal isotropic macroturbulent velocity function was assumed. The result appears to be sensitive to the assumed shape of the macroturbulence function.
    Keywords: ASTROPHYSICS
    Type: Astrophysics and Space Science; 84; 2, Ju; June 198
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  • 16
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    On the structure of the outer layers of cool carbon stars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Exposures on the spectra of four late C-type stars have been made with the IUE satellite in the wavelength range of the LWR camera (1900-3200 A). Two Mira variables near maximum light and two semiregular variables were observed. Although the exposure times used, which range up to 240 min in the low-resolution mode, were more than sufficient to record the continuum and emission lines of Mg II, Fe II, and Al II in normal M stars of similar magnitude and temperature, no light was recorded. It is concluded that the far-ultraviolet continuum is strongly depressed in these cool carbon stars. The absence of UV emission lines implies either that the chromospheric lines observed in M stars require an ultraviolet flux for their excitation, or that cool carbon stars have no chromosphere at all or that the opacity source is located above even the emission-line-forming region. This opacity source, which is probably some carbon condensate since it is weak or absent in M stars while absorbing strongly in C stars, is discussed both in terms of the chromospheric interpretation of the emission lines and in terms of their shock-wave interpretation.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 111; 1, Ju; July 198
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  • 17
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    A precessing relativistic jet model for 3C 449 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: It is shown that the radio structure of 3C 449 can be matched with a model in which the jets are precessing and have relativistic (beta greater-than or equal to 0.4) velocities. The best-fit model implies a precession period of about 100,000 yr and a cone angle which increases with time. A similar model may be relevant for the radio structure of 3C 31. A brief discussion of the implications for 3C 449 is given.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 258
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  • 18
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    Collapse of accreting, rotating, isothermal, interstellar clouds (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The evolutions of the envelopes of collapsing, accreting, isothermal clouds have been numerically calculated for both spherically symmetric and rotating (axisymmetric) clouds. The results provide a cohesive picture of isothermal collapse, and their relationship to previous numerical calculations and similarity solutions is discussed. Even with a large initial rotation rate, the majority of the cloud envelope is accreted, in one case leaving behind a large-scale circulation current. The calculations are performed for both initially uniform density and centrally condensed clouds. Density and velocity profiles for a wide variety of observed systems are compared with those obtained in this study, providing a preliminary assessment of the stage of evolution and initial structure for the observed systems.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 258
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  • 19
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    Laboratory measurements of amorphous silicate smokes and the infrared spectra of oxygen-rich stars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The infrared spectra of smokes condensed from SiO-H2 and Mg-SiO-H2 vapors and of smoke samples annealed for various times at 1000 K and 1250 K are presented. The spectra of these materials show features in the 8-25 micron interval in addition to the well-known bands near 10 and 20 microns. It is suggested that these features may correspond to weak structures that can be seen in the infrared spectra of oxygen-rich stars. Observations are needed to determine the reality and characteristics of such weak features.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 257
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  • 20
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    The distribution of free electrons in the inner Galaxy from pulsar dispersion measures (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-18096)
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 257
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  • 21
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    Star formation - The influence of velocity fields and turbulence (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: It is shown that the Jeans mass for gravitational collapse can be very much reduced by the influence velocity fields, even when allowance is made for non-isothermal gas behavior. We examine the role of turbulence in establishing the initial stellar mass function and show that the flattening and/or turnover at the low mass end may be a signature of interstellar turbulence. We consider also the implications of primordial turbulence for the formation of stars in the early universe.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 256
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  • 22
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    A model of a comet coma with interstellar molecules in the nucleus (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The coma of a comet is modeled assuming the icy nucleus contains interstellar molecules. This composition overcomes discrepancies between observation and earlier model predictions for CN, C2, C3, and NH2 abundances. It is found that the abundances of CN, C2, and C3-bearing compounds in the nucleus must be constrained to trace amounts in order to account for the observed column densities. NH3 also cannot be abundant by more than about 1%. The model gives good agreement with observed relative ranges of neutral species in the coma as well as with their observed relative intensity dependence on heliocentric distance. The size of the nucleus and the heliocentric ranges considered are relevant to comet Halley.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 108; 2, Ap; Apr. 198
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  • 23
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    Radial evolution of power spectra of interplanetary Alfvenic turbulence (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-18097)
    Keywords: ASTROPHYSICS
    Type: Journal of Geophysical Research; 87; May 1
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  • 24
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    Infrared emission line studies of the structure and excitation of H II regions (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Maps of five H II regions in one or more of the infrared fine-structure lines of Ne II (12.8 microns), Ar III (9.0 microns), and S IV (10.5 microns) have been obtained with angular resolutions ranging from 4 to 7 arcsec. The observations are used to discuss the morphology and excitation of these nebulae. Considerable diversity is found in the structures of the nebulae, probably resulting from differences in their ages and the circumstances of their formation. In all cases, more ionizing luminosity than would be provided by a single dominant ionizing star appears to be required, although uncertainties in the model nebulae make this conclusion uncertain.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 255
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  • 25
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    Evidence for extended X-ray emission from globular clusters (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Deep exposures with the Einstein Observatory show evidence for diffuse X-ray emission from three globular clusters. One possible interpretation of these observations is that the interaction between a cluster wind and a hot gaseous galactic halo is being observed. The one cluster for which the proper motion has been measured is consistent with this interpretation.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 254
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  • 26
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    A different type of maser star (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A systematic survey of short-period, semiregular variable stars has been made resulting in the detection of six new water masers. Of the 14 short-period maser stars now known, nine are classified as SRb variables. All are very late spectral type SRb's, typically M7, while the overwhelming majority of normal SRb stars is M4 to M6. Their 2.2-11 micron color indices are among the lowest of any known maser stars. They are presumably less dusty as well. Four of the SRb stars and two of the remainder do not obey the correlation between period and velocity spread of the emission features that is found for the Mira and long-period, semiregular variables. Finally, high galactic latitudes dominate; 13 of the 14 are in excess of 13 deg, and nine of these are greater than 25 deg. These facts suggest that the short-period semiregular variables - particularly in SRb stars - may be a very different type of maser star than the Mira and long-period semiregular variables.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 254
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  • 27
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    The discovery of 50 minute periodic absorption events from 4U 1915-05 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An analysis of X-ray observations shows that the steady flux from 4U 1915-05 undergoes periodic absorption dips with a period of 50 minutes. This period most probably represents the underlying orbital period of the system, and variations in the depth and duration of these events suggest that they are caused by a bulge on the edge of the accretion disk at the point where the gas stream impacts the disk. The mass-losing star in this system is probably a low-mass white dwarf, and the spectrum of the dips indicates that the metallicity of the absorbing material is at least a factor of 17 below solar values. The discovery of the 50-minute binary period supports earlier suggestions that X-ray burst sources are in binary systems.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 253
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  • 28
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    Search for interstellar superheavy hydrogen (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Models for fundamental physical interactions allow for the existence of stable or nearly stable elementary particles much heavier than the proton. Stellar spectra were searched for a positively charged superheavy particle, X(+), which, with a bound electron, should appear as apparently superheavy neutral hydrogen in the interstellar medium. An upper limit for the abundance of X relative to normal hydrogen in the line of sight toward the bright star gamma Cassiopeiae is 2 x 10 to the -8th.
    Keywords: ASTROPHYSICS
    Type: Science; 216; Apr. 2
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  • 29
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    Resonant electrodynamic heating of stellar coronal loops - An LRC circuit analog (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The problem of electrodynamic coupling of stellar coronal loops where beta is less than 1 to underlying velocity fields where beta is greater than approximately 1 is treated. A rigorous analysis reveals that the physics can be represented by a simple yet equivalent LRC circuit analog. This derived analog suggests the existence of global structure oscillations which resonantly excite internal field line oscillations at a spatial resonance within the coronal loop. Even though the width of this spatial resonance, as well as the induced currents and coronal velocity field, within the resonance region explicitly depends on viscosity and resistivity, the resonant form of the generalized electrodynamic heating functions is virtually independent of irreversibilities. This is a classic feature of high-quality resonators that are driven externally by a broad-band source of spectral power.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 254
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  • 30
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    Observations of interstellar zinc (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: IUE observations toward 10 stars have shown that zinc is not depleted in the interstellar medium by more than a factor of two, suggesting that its abundance may serve as a tracer of the true metallicity in the gas. A result pertinent to the history of nucleosynthesis in the solar neighborhood is that the local interstellar medium has abundances that appear to be homogeneous to within a factor of two, when integrated over paths of about 500 pc.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 254
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  • 31
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    Electromagnetic cascades in pulsars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The development of pair-photon cascades initiated by high energy electrons above a pulsar polar cap is simulated numerically. The calculation uses the energy of the primary electron, the magnetic field strength, and the period of rotation as parameters, and follows the curvature radiation emitted by the primary, the conversion of this radiation to e(+)e(-) pairs in the intense fields, and the quantized synchrotron radiation by the secondary pairs. A recursive technique allows the tracing of an indefinite number of generations using a Monte Carlo method. Gamma-ray and pair spectra are calculated for cascades in different parts of the polar cap and with different acceleration models. It is found that synchrotron radiation from secondary pairs makes an important contribution to the gamma-ray spectrum above 25 MeV, and that the final gamma-ray and pair spectra are insensitive to the height of the accelerating region, as long as the acceleration of the primary electrons is not limited by radiation reaction.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 252
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  • 32
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    Model atmospheres, predicted spectra, and colors (1982)
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    Publication Date: 2011-08-18
    Description: Theoretical models of stellar atmospheres and the process of forming a spectrum are reviewed with particular reference to the spectra of B stars. In the case of classical models the stellar atmosphere is though to consist of plane parallel layers of gas in which radiative and hydrostatic equilibrium exists. No radiative energy is lost or gained in the model atmosphere, but the detailed shape of the spectrum is changed as a result of the interactions with the ionized gas. Predicted line spectra using statistical equilibrium local thermodynamic equilibrium (LTE), and non-LTE physics are compared and the determination of abundances is discussed. The limitations of classical modeling are examined. Models developed to demonstrate what motions in the upper atmosphere will do to the spectrum and to explore the effects of using geometries different from plane parallel layer are reviewed. In particular the problem of radiative transfer is addressed.
    Keywords: ASTROPHYSICS
    Type: B stars With and Without Emission Lines, Parts 1 and 2; p 165-197
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  • 33
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    Isolated grain condensation behavior: Computation methods and first results (1982)
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    Publication Date: 2011-08-18
    Description: A set of efficient programs for calculation of condensation behavior in a system with either solar or carbon-rich elemental composition was developed to treat the course of condensation at very low pressures. These programs were applied to the problem of condensation at very low pressures. The minerals produced in the stellar and nova-related processes under study, including carriers of important volatile elements such as carbon and nitrogen, are candidates for accretion into meteorite parent bodies and planets, and may still be discernible in the enstatite chondrites.
    Keywords: ASTROPHYSICS
    Type: Planetary Atmospheres Program; p 36-47
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  • 34
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    Theory of electron-positron showers in double radio sources (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: A black hole of mass of about 300 million solar masses is assumed to be present in the nucleus of an active galaxy or quasar. With an axial magnetic field near 1000 gauss, a potential drop 10 to the 19th volts is generated by the unipolar induction of a rotating accretion disk surrounding the black hole. The possibility that the acceleration of electrons or positrons in the unipolar fields initiates an electromagnetic cascade shower at distances at least 10 to the 16th cm from the black hole is investigated. The scattering medium for the shower is considered to be the spectrum of low energy photons originating from the inner region of the disk. It is found that at completion of the cascade, power-law energy spectra of relativistic electrons and positrons and of gamma-rays emerge under appropriate conditions. If the cascade-initiating particles are collimated, the electrons and positrons emerge in a collimated beam. Such beams may power extragalactic double radio sources.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 262
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  • 35
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    The WC6 star HD76536 compact companion (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The variability of HD76536 was observed by IUE. Photometric variability is confirmed by measurements with the IUE fine error sensor. Profile changes in the ultraviolet emission lines and stellar wind absorptions were studied. Data favor a binary model with a low luminosity (perhaps compact) secondary.
    Keywords: ASTROPHYSICS
    Type: ESA 3rd European IUE Conf.; p 269-271
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  • 36
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    On redistribution and the equations for radiative transfer (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The derivation of the equations of statistical equilibrium are outlined, starting from the quantum density-matrix equations, drawing particular attention to the approximations and assumptions used in the development of tractable expressions. Then, using the quantum-fluctuation-regression theorem, emission and absorption coefficients are obtained for multilevel atomic systems which are nondegenerate except for m-substates. These coefficients are valid to first order in the incident intensity. Possible extensions to higher intensity broadband incoherent fields are suggested.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 260
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  • 37
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    Neutral hydrogen in elliptical galaxies with nuclear radio sources and optical emission lines (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-22136)
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 259
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  • 38
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    Sensitive ammonia observations in the southern hemisphere (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The 64-m spacecraft communication antenna of the NASA-JPL Deep Space Network has been equipped for spectral line observations at K band (18-25 GHz). To demonstrate the potential of this system, preliminary observations of the (1, 1) transition of ammonia are reported for a selection of eight southern molecular clouds. Estimates of gas density and ammonia column density are reported for six sources.
    Keywords: ASTROPHYSICS
    Type: Astronomical Journal; 87; Aug. 198
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  • 39
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    A search for fragmentation debris near Ursa Major Stream stars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Accretion models of planet formation and the early cratering history of the solar system suggest that planet formation is accompanied by a cloud of debris resulting from accumulation and fragmentation. A rough estimate of the infrared luminosities of debris clouds is presented for comparison with measured 10-micron luminosities of young stars. New measurements of 13 F, G, and K main-sequence stars of the Ursa Major Stream, which is thought to be about 270-million years old, place constraints on the amount of debris which could be present near these stars.
    Keywords: ASTROPHYSICS
    Type: Icarus; 50; Apr. 198
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  • 40
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    Large-scale magnetic fields in spiral galaxies (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The optical polarization vectors which measurements have shown to be parallel to the pronounced dark lanes of such galaxies as NGC 5128 and 4590 are interpreted as the consequence of a large scale, systematic field parallel to the dark lane that leads to the alignment of the grains. It is suggested that such polarization may also be produced by scattering off grains concentrated in the dark lane. It is recommended that there be further observational tests of the hypothesis that the observed polarization indicates the magnetic field in the galaxy.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 258
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  • 41
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    Cygnus X-3 observed at photon energies above 500 GeV (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: High-energy gamma rays from Cyg X-3 have been observed with the twin 11-m mirrors of NASA JPL's solar energy facility, using the atmospheric Cerenkov technique, resulting in data from about 100,000 air shower events with an approximate threshold energy of 500 GeV for the August 29 to September 6, 1981 period. A positive signal whose amplitude is 10.9 + or - 2.5% of the background cosmic ray rate appears near phase 0.6 of the 4.8-hour cycle, where phase 0.0 corresponds to minimum X-ray emission. This, together with previous Cerenkov detections, indicates that the high energy emission from Cyg X-3 is evolving on a time scale of a few years and suggests that the present form of the system has a recent origin.
    Keywords: ASTROPHYSICS
    Type: Nature; 296; Apr. 8
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  • 42
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    Parity nonconservation and the origin of cosmic magnetic fields (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Three mechanisms of cosmic magnetic field generation are discussed: (1) asymmetric decay of particles emitted by rotating black holes; (2) asymmetric proton emission by black holes due to weak radiative corrections, and (3) equilibrium parity-violating currents. It is shown that all three mechanisms can produce a seed field sufficiently strong to account for the present galactic fields.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 254
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  • 43
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    Cometary NH - Ultraviolet and submillimeter emission (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A description is presented of the results of computer calculations on the molecule NH, which is an important constituent of cometary comae, and a probable, but an as yet undetected, interstellar species. Attention is given to spectroscopic properties, the treatment of solar spectral data, and radiative transfer calculations. The results of calculations for the Einstein A-coefficients are given in an appendix, where the entries for the X-X and A-A transitions depend on the assumed permanent electric-dipole moment squared. Rotational-spin-Lambda-doublet energy levels used for statistical equilibrium population densities are listed in a table.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 253
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  • 44
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    Interplanetary gas. XXVIII - A study of the three-dimensional properties of interplanetary sector boundaries using disconnection events in cometary plasma tails (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Studies of the solar wind on the basis of cometary plasma tail observations are considered. Niedner and Brandt (1978, 1979) have concluded that the plasma tail frequently disconnects from the cometary head, and that these disconnection events (DEs) are produced by magnetic reconnection at sector boundary passages. They proposed that the disconnections are a natural combination of Alfven's model and the solar-wind sector structure first discovered by Wilcox and Ness (1965). The DEs can be utilized as probes of interplanetary sector structure. Correlations between DEs and sector boundaries observed at earth are considered, and sector boundary properties deduced from DEs are discussed. Attention is given to a review of the warped sheet model, the latitude extent of sector structure, the sector boundary tilt, and specific sources of error in the tilt angles derived from DEs.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal Supplement Series; 48; Jan. 198
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  • 45
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    On syntheses of the X-ray background with power-law sources (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The conditions under which the combined emission from power-law sources can mimic the X-ray background (XRB) spectrum in the 3-50 keV range are considered in view of HEAO 1 A-2 experiment measurements, and it is confirmed that a good fit may be obtained. The required spectral properties of the component sources differ, however, from those observed for local active galactic nuclei. Constraints are deduced for both the low-luminosity extension and evolution of such local objects, and it is shown that any other class of sources contributing to the X-ray background must be characterized by an energy spectral index lower than about 0.4, which is the mean index of the XRB, and exhibit steeper spectra at higher energies.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 253
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  • 46
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    Hot wind from Gamma/2/ Velorum observed in the ultraviolet carbon lines (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The close binary system Gamma(2) Vel, consisting of a WC8 and an O9 I star, has been observed in the ultraviolet at various phases. Preliminary analysis of selected data shows that the temperature of the stellar wind from this binary increases outward. This suggests that an additional source of energy other than radiation pressure may exist for the wind. The mass flow occurs in all directions from the binary. However, there is evidence of an increase in the mass flow through the third Lagrangian point, although from the extant data it is not possible to decide whether or not a similar increase in the mass outflow occurs through the second Lagrangian point. There is also evidence of mass surge, which probably is independent of orbital phase.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 252
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  • 47
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    Neutral hydrogen emission and absorption in three active Irr II galaxies (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Peak optical H I absorption depths of 10% are found in a neutral hydrogen emission-absorption study of the active-nucleus Irr II galaxies NGC 520, 5363, and 5506. It is suggested that the absorption is due to a few standard clouds within several hundred parsecs of the nucleus, in the narrow-line emission region. The width of the absorption features is interpreted as being due to random motions of the gas within the absorbing clouds, in contrast to the large widths of the emission features that are due to the overall rotation of the galaxy.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 252
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  • 48
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    The remarkable 400 micron source NGC 6334/I/North/ (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Observations at 400 microns of the NGC 6334 complex have confirmed the discovery of an unusual 1000-solar mass object, NGC 6334/I(North), which was not detected by broad-band 100-micron survey observations. The results suggest that this cool source (T = 19 + or - 5 K) is an active star formation region in a very early stage of evolution. The observed infrared luminosity of the source, 7000 solar luminosities, requires the presence of one or more embedded B stars or the formation of a dense protostellar core. Derived dust and gas densities agree well with results from molecular line observations of the complex. Nearby 100 micron peaks I and V were also observed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 259
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  • 49
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    The path and surviving tail of a comet that fell into the sun (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A satisfactory orbital solution for Comet Howard-Koomen-Michels 1979 XI is found on the assumption that the comet's line of apsides coincided with that of the Kreutz sungrazing comet group. The derived perihelion distance then shows that this is the first known case of a comet falling into the sun. A dust tail that survived the comet is studied as a particle flow phenomenon controlled by no force other than solar gravity and solar radiation pressure. The tail's outline is interpreted in terms of an onset of dust production, a peak repulsive force on the particles, and a circumsolar dustfree zone due to particle sublimation. It is shown that the surviving debris consisted mostly of absorbing, submicron size particles in hyperbolic trajectories convex to the sun and curving toward the earth. The tail width may be a product of the interaction of charged dust in the tail with a complicated structure of the coronal magnetic field.
    Keywords: ASTROPHYSICS
    Type: Astronomical Journal; 87; July 198
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  • 50
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    Extragalactic gamma radiation - Use of galaxy counts as a galactic tracer (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-20109)
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 109; 2, Ma; May 1982
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  • 51
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    The light curve of periodic comet Halley 1910 II (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Photometric parameters for periodic comet Halley 1910 II have been derived from 144 total visual magnitude estimates. The pre-perihelion data are best represented by an absolute magnitude of 5.47 and a power-law exponent of 4.44; post-perihelion results show that the absolute magnitude brightened to 4.94, and the exponent decreased to 3.07. Only small fluctuations in brightness about the power-law solutions are noted. Based on these results, a forecast of the visual brightness of periodic comet Halley's 1985-1987 apparition is presented.
    Keywords: ASTROPHYSICS
    Type: Astronomical Journal; 87; June 198
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  • 52
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    Large-scale variations of the interplanetary magnetic field - Voyager 1 and 2 observations between 1-5 AU (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-13594)
    Keywords: ASTROPHYSICS
    Type: Journal of Geophysical Research; 87; June 1
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  • 53
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    Accretion disk coronae (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-20106)
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 257
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  • 54
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    Solar-stellar astrophysics (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Nonthermal physical processes in the solar atmosphere are discussed. The solar atmospheric regions are defined, and solar convection and its phenomena are explained. The relationship of the solar dynamo, magnetic field, and flares is explored. The solar atmospheric velocity fields are discussed, and the unresolved problem of the nature of atmospheric heating is detailed. The solar wind heating and acceleration are discussed and the need for global solar atmospheric models is emphasized. The application of these solar nonthermal processes to the stars in general is then taken up, employing the same categories as were applied to the solar atmosphere.
    Keywords: ASTROPHYSICS
    Type: Comments on Modern Physics; vol. 9
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  • 55
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    Energy distribution in the strongly interacting binary system SX Cassiopeiae (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: IUE spectra and optical scans covering the 110-680 nm interval were obtained in a search for a source which would resolve the anomalous presence of strong Balmer emission lines in the SX Cas eclipsing binary system, which is inconsistent with the usual spectral classification of the components as A6 III + G6 III. The IUE spectra unexpectedly show such strong emission lines as those of C IV, N V and Si IV, which require higher temperatures that the already anomalously high Balmer lines, and a continuum several magnitudes higher than the extrapolated continuum of an A6 star. A model in which the UV continuum originates in the transition zone between the A6 star and an accretion disk fails to reproduce the observed energy distribution. A revision of component spectral types to B7 + K3 III removes the UV excess.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 256
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  • 56
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    Apparent superluminal motion in the quasar NRAO 140 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Very long baseline interferometer (VLBI) measurements of the compact radio structure in the quasar NRAO 140 (z = 1.258) have been obtained at three epochs at a wavelength of 2.8 cm. These observations indicate that the two most compact radio components are separating at an angular rate of 0.10-0.14 milli-arcsec per year. For cosmological distances H sub 0 = 50 and q sub 0 = 0, this corresponds to a velocity of separation (in the quasar's rest frame) of 10 + or - 2 times the speed of light, c; for H sub 0 = 100 and q sub 0 = 1, the value is (3.1 + or - 0.6) c. Other interpretations of the temporal changes in correlated flux density and closure phase are discussed and are considered unlikely. The derived velocities are consistent with an earlier prediction that the separation velocity should be greater than about 4 c. Extrapolation back to the epoch of zero separation indicates that the expansion originated between late 1963 and late 1968 (under the assumption of constant velocity). This range includes the beginning of an isolated outburst in flux density at 2.8 cm. These results cannot be used to make any statements concerning the validity of cosmological interpretations of QSO redshifts.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 255
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  • 57
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    Rotational temperatures of cyanodiacetylene in Sagittarius B2, TMC-1, and IRC +10216 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 254
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  • 58
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    The local interstellar medium (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Analysis of the velocities of optical interstellar lines shows that the sun is immersed in a coherently moving local interstellar medium whose velocity vector agrees with that of the interstellar wind observed through backscatter of solar H Ly-alpha and He lambda 584 photons. The local interstellar medium consists of both cool clouds and warm intercloud medium gas, has a mass of perhaps approximately 30 solar masses, does not have severe depletion of trace elements from the gas phase, and appears to be material which has been shocked and accelerated by stellar winds and supernovae associated with the Sco-Oph OB association.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 254
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    4C 18.68 - A QSO with precessing radio jets (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: High-resolution VLA radio maps at 20 cm and 6 cm wavelengths of the quasar 4C 18.68 reveal an extended halo of about 20 arcsec containing complex curved structures extending east and west from the central source. The central source has a flat spectrum, while the spectrum generally steepens with distance from the center of the structure. The details of the structure and polarization of the emission suggest relativistic ejection in opposing directions by a precessing or rotating double jet with a period of about 50,000 years, consistent with the presence of two interacting massive bodies in the central source.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 253
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  • 60
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    On the folding phenomenon of comet tail rays (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: It is shown that the folding phenomenon of the comet tail rays is compatible with the Ferraro isorotation law if the comet tail magnetic field has no azimuthal component, that is, B sub phi (the polar angle) equals zero. Considering electric drift due to convectional electric fields, a formula is obtained for the angular rate of a ray closure which reduces to that of Ness and Donn (1966) if the velocity profile across the tail is linear. The magnetic field B of approximately 20-40 gammas in the coma and less than about 10 gammas in the distant tail is estimated under typical solar wind conditions at 1 AU.
    Keywords: ASTROPHYSICS
    Type: Royal Astronomical Society; vol. 198
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    The derivation of Halley parameters from observations (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Nominal value model parameters for the nucleus (size, mass, rotation, albedo, hydrogen production) the dust and gas for P/Halley at 0.9 AU postperihelion are derived from the light curve and spectra of Halley and by modeling the effect of the nongravitational forces, e.g., the outgassing rocket type effect of the nucleus. In those cases where Halley observations are not sufficient, the average value derived from a larger set of other comets is used, or data from comet Bennett, Halley's best analog, are taken. A flow diagram shows how the parameter values are derived and to what extent these derived values are interdependent. Previously announced in STAR as N82-23097
    Keywords: ASTROPHYSICS
    Type: (ISSN 0273-1177)
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    Einstein Observatory results on active galactic nuclei (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The results of Einstein Observatory surveys of active galactic nuclei (AGN) are reviewed. The ubiquity of X-ray emission from AGNs was confirmed. The relations between X-ray and optical luminosities, between X-ray and radio properties, and between X-ray and optical-UV line emission found by the surveys are summarized and briefly discussed. The possible causes of observed X-ray emission from jets in Cen-A, 3C273, and M87 are considered. The active nucleus discovered in the optically 'dull' galaxy NGC 4156 is covered, and a model for NGC 4151 based on detailed spectral studies is briefly discussed. This model establishes the global symmetry of the AGN clouds, their approximate sizes, and their ionization state. Difficulties encountered in attempting to explain the cosmic X-ray background in terms of AGN contributions are addressed.
    Keywords: ASTROPHYSICS
    Type: (ISSN 0273-1177)
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    IUE observations of cataclysmic variables (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The four years of IUE operation have revealed that the ultraviolet region of the spectrum contributes a dominant share of the emerging energy from cataclysmic variables and provides important clues to the physical nature of these systems. The implications of the continuum flux distributions and line spectra for the determination of the accretion rates and mass loss rats are considered.
    Keywords: ASTROPHYSICS
    Type: (ISSN 0273-1177)
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    A search for frosts in Comet Bowell /1980b/ (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Infrared observations of Comet Bowell represent the first search for frost signatures in a comet beyond 2 AU from the sun. Broad- and narrowband photometry has been obtained as well as CVF spectrophotometry of this comet and there is no evidence for absorption features in the spectral area between 1.25 and 2.3 microns. Models of the coma have been generated which constrain the volatile content of the grains an; are in agreement with the observed albedo. The darkness of the coma particles at large heliocentric distances indicates a low albedo nucleus as well. Brightness variations during the observing period seem to indicate an active nucleus at 4.5 AU from the sun.
    Keywords: ASTROPHYSICS
    Type: Astronomical Journal; 87; Dec. 198
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    A comparison of the X-ray properties of X Persei and Gamma Cassiopeiae (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The greater than 0.0001 solar mass/year loss rates required to power X-ray sources, if associated compact objects are white dwarfs, are many orders of magnitude greater than even the highest estimates for the main sequence Be stars Chi Per and Gamma Cas, confirming that the compact objects in these systems are neutron stars. While observed mass loss rates are of the order of that required to power the X-ray emission from a neutron star, X-ray measurements have established rates at least an order of magnitude above UV estimates, supporting earlier suggestions of an inclination dependence in the mass loss from rapidly rotating main sequence OB stars which results in mass loss rates in the orbital plane that are at least one order of magnitude higher, or terminal velocities that are at least a factor of 2.0 lower, than is indicated by UV measurements.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 263
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  • 66
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    Visual and infrared observations of the distant Comets P/Stephan-Oterma /1980g/, Panther /1980u/, and Bowell /1980b/ (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The paper reports combined visual imagery and spectroscopy, near-infrared spectroscopy, and broadband infrared photometry of comets P/Stephan-Oterma (1980g), Bowell (1980b), and Panther (1980u) at intermediate heliocentric distances. The visual data indicate the existence of solid grains in extended halos around the nuclei of the three comets. Broadband near-infrared and thermal infrared measurements of Comet Panther suggest the presence of 2-4-micron-radius particles in the coma which most likely contain molecules incorporating the N-H bond, but which are more complex and less volatile than NH3. Such molecules can be produced in the grains by cosmic-ray reprocessing. Near infrared spectral features identical to those seen in comet Panther similary suggest the presence of a molecule incorporating the N-H bond in comet Bowell.
    Keywords: ASTROPHYSICS
    Type: Astronomical Journal; 87; Dec. 198
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    The relationship between carbon monoxide abundance and visual extinction in interstellar clouds (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Carbon monoxide column densities are compared to visual extinctions toward field stars in the rho Oph and Taurus molecular cloud complexes. The relationship of C(0-18) column density to extinction is established, and new determinations for (C-13)O column densities are given for a range of visual extinctions extended to beyond 20 mag. A prescription for determining hydrogen column densities and masses of molecular clouds from observations of CO isotopes is presented and discussed critically. These measurements agree well with the predictions of gas phase chemistry models which include chemical fractionation and selective isotopic photodestruction. The functional dependence of the C(O-18) column density on extinction is characterized by two different regimes separated by a distinct transition observed to occur at 4 mag in both molecular cloud complexes, whereas the functional dependence of (C-13)O is quite different in the two regions. Some saturation is found to occur for C(O-18) emission at high visual extinction and use the rarer isotopic species C(O-17) and (C-13)(O-18) to correct for it.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 262
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    Relativistic precessing jets in quasars and radio galaxies - Models to fit high resolution data (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The formulation of generalized models tracing the geometry and intensity of the synchrotron emission from precessing, twin, relativistic jets as projected on the plane of the sky is presented. It is shown that neither the shape of the image nor its relative intensities are altered by including the effects of a cosmological redshift and a relative velocity between the source and observer. The models are fitted to the available data for several quasars and radio galaxies and demonstrate the plausibility of the phenomenon. Probable selection effects are considered and diagnostics given for recognizing objects showing this behavior. In the radio galaxies considered, velocities up to about 0.2c and precession periods of 1,000,000 yr are deduced. In the QSOs investigated, velocities of 0.7c and greater are found and periods of order 10,000 yr. In some cases precession cone angles increase with time. Consequences in terms of lifetimes of QSO behavior and binary supermassive objects are discussed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 262
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  • 69
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    Observations and dynamics of plasma tails (1982)
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    Publication Date: 2011-08-18
    Description: Observations of plasma tails of comets are reviewed. The basic morphology of plasma tails is examined. It is shown that two features, viz., the ray-folding phenomenon and disconnection events, are essential to a general understanding of plasma tail phenomena. A qualitative model of disconnection events is proposed that is based on the cyclic occurrence of magnetic reversals in the solar wind.
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  • 70
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    Photochemical processes in the inner coma (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Models for the inner-coma chemistry of comets are reviewed. The physics relevant to the coma's chemistry is summarized, and the interaction of solar radiation with the coma is described, along with photolytic and chemical processes. The formation and destruction of several observed species are traced through a chemical reaction network, and model results are compared with observations. The species considered include CN, C2, C3, NH2, CH, CO, CO(+), OH, H2O, HCO, C2H4, and C2H3. The models most consistent with observations are shown to indicate that only trace amounts (2% in all) of molecules bearing CN, C2, C3, and NH2 can be present in the nucleus of a comet.
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  • 71
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    Abundances in five nearby galactic H II regions from infrared forbidden lines (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Airborne measurements of the Ar II (6.99 micron) and S II (18.7) micron lines for five compact H II regions in the solar neighborhood are presented, as well as 2-4 micron and 8-13 micron spectroscopy where available. From these data and radio data, lower limits to the elemental abundances of Ar, Ne, and S are deduced. Some of these H II regions suffer substantial nebular extinction, and some are extended. After correcting for beam size effects an extinction, it is found that four of the objects are consistent with standard abundances, within the uncertainties of correcting for unobserved ionization states. A Perseus arm object, S156, is apparently overabundant in sulfur.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 262
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  • 72
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    Turbulent compressible convection in a deep atmosphere. I - Preliminary two-dimensional results (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The turbulent convection of a compressible fluid in a deep atmosphere is simulated by two-dimensional numerical computations, displaying coexisting 'cells' whose sizes range from the total depth of the convection zone to the smallest scale height at the top. While the largest cells traverse the entire zone, smaller ones are clustered near the top. The vertical correlation length of the vertical velocity is proportional to the local pressure or density scale height, in a way reminiscent of the concept of mixing length.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 263
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  • 73
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    Detection of interstellar sodium hydroxide in self-absorption toward the galactic center (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A weak self-absorbed emission line, which is identified as the J = 4-3 transition of sodium hydroxide, has been detected in the direction of Sgr B2(OH). The correspondingly weak Sgr B2(QH) emission line U75406, previously reported as an unidentified spectral feature by other investigators, is consistent with the J = 3-2 transition of sodium hydroxide. This detection may represent the first evidence of a grain reaction formation mechanism for simple metal hydroxides. The detection of H62 Delta toward Orion A is also reported.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 262
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  • 74
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    Special types of B stars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The properties of the Beta Cephei stars are examined with emphasis on spectral types, luminosities, periods, and light and velocity variations. Typical members of the group and their position in the observational and theoretical HR diagram are discussed. Those B stars with anomalous spectra (chemically peculiar) are considered including hot subdwarfs, extreme helium, weak helium, strong helium, helium variable, magnetic and mercury-manganese stars.
    Keywords: ASTROPHYSICS
    Type: NASA, Washington B Stars With and Without Emission Lines, Parts 1 and 2; p 147-163
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  • 75
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    Structure and origin of cometary nuclei (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-13035)
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  • 76
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    The interrelation of cosmic gamma-rays and interstellar gas in the range l:65-180 deg (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: New date on the distribution of molecular hydrogen in the first and second quadrants allow a detailed analysis of the relationship between the column density of gas (in all major forms) and the intensity of cosmic gamma-rays in the Galaxy. It is concluded that most of the features observed in the gamma-ray map can be explained in terms of cosmic-ray interactions with the gas in the ISM, with molecular hydrogen playing an important role. The cosmic-ray intensity in the important production regions appears to be roughly independent of galactocentric distance, R, for l:65-100 deg and to fall off slowly with R for l:100-180 deg.
    Keywords: ASTROPHYSICS
    Type: Royal Astronomical Society; vol. 201
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  • 77
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    On the flaring of cometary plasma tails (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Assuming that hypersonic pressure balance with the solar wind governs the shape of plasma tails, it is found that the gas pressure of tail ions and the magnetic field strength at the flanks of the ionopause control the flaring state. The gas pressure exhibits the larger effect: for constant pressures above a certain critical value, the tail flares essentially without limit, while for smaller values the tail flares only near the head (becoming cylindrical at greater distances). The influence of the magnetic field is that the tail flares to larger distances the higher the field strength at the flanks of the ionopause. The observed variability in flaring (and the implied differences in gas pressure and magnetic field) are throught to be the result of changes in the position and shape of the sunward cometary ionopause. Insertion of reasonable comet and solar wind parameters into the pressure balance equations is found to give good agreement with the observations.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 262
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  • 78
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    Gas in the galactic halo (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The evidence that gas exists in the halo of the Galaxy is examined. The likely properties of halo gas intervening between QSOs and the Galaxy are extracted from observations of the galactic halo. The available data discussed include 21-cm observations, optical absorption lines, ultraviolet lines, and X-ray observations. The possible existence of a cosmic ray halo is assessed, and the relationship of galactic size to the extent of the halo is examined. The main physical constraints on the gas in the halo are detailed, including the radiation field, particle density, temperature, mass in the halo gas, and abundances. Models for the gas in the halo are summarized. It appears that the distribution of gas in the galactic halo is an expanded disk not more than 10 kpc thick. At low column densities, the Galaxy could extend out to several times the Holmberg radius. The disk may be photoionized on the outside by the QSO background radiation.
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  • 79
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    A technique for measuring magnetic fields on solar-type stars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A method is developed and tested by which magnetic-field strengths and area filling-factors of magnetic regions on late-type stars may be inferred from high-resolution, absorption-line profiles that have been broadened by the Zeeman effect. The technique involves fitting such profiles with a triplet of components, the shape of which is derived from profiles of lines of low Zeeman sensitivity. Tests of the systematic and random errors indicate that such magnetic flux measurements have an uncertainty of 20% for stars with field strengths of 2000 gauss if at least 10% of the stellar surface contains magnetic regions.
    Keywords: ASTROPHYSICS
    Type: Astronomical Society of the Pacific; vol. 94
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  • 80
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    Asymmetric emission-line regions with out-flowing mass in QSOs and the z/ab/ at least equal to z/em/ systems (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A heuristic asymmetrical model for a quasar emission-line region, with material streaming out, is described. The physical parameters are essentially the same as those of static models; the geometry turns out to be the dominant factor in determining the emission line profiles. Calculations are carried out for a variety of parameterized flow models and for the Blumenthal and Mathews (1975) theoretical model of a radiatively driven flow. The emission-line profiles are insensitive to the details of the acceleration, the filling factor, and the ionization profile. Absorption is assumed to take place in stationary matter in the QSO's galaxy or associated group or cluster, so that z(ab) is identified with the cosmological redshift. Due to the flow, the emission-lines are shifted with respect to the absorption-lines; in cases of a flow directed towards the observer systems with z(ab) at least equal to z(em) result. The distribution of absorption redshifts is symmetric about z(em).
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 115; 2, No; Nov. 198
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  • 81
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    Ultraviolet shell formation at V1016 Cygni (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A recent 330 minute high-resolution International Ultraviolet Explorer (IUE) spectrogram of V1016 Cygni shows splitting of the 1550 A component of the C IV resonance doublet, suggesting that a nebular shell is in the process of formation. An expansion velocity of 15 km/s is indicated by the IUE data and corresponds to the low range encountered with normal planetary nebulae, but IUE data of V1016 Cyg, taken approximately one year earlier, do not show split C IV lines. The recent IUE observations are consistent with VLA contour maps at 1.3 cm made by Newell and Hjellming (1981) and by Hjellming and Bignell (1982) that morphologically show an extended shell-type object. Thus, V1016 Cyg may have undergone an event which forms a planetary nebula.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 263
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  • 82
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    VLBI observations of the nucleus and jet of M87 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The nucleus and jet of M87 was mapped with an eight-station very long baseline interferometric array at 18 cm wavelength with high dynamic range. It was found that the nucleus of M87 consists of a core-jet structure with a peak brightness temperature greater than 10 to the 10th K. Emission is shown to extend for more than 50 milli-arcsec with a brightness temperature exceeding 10 to the 8th K along a position angle of 288 degrees, which precisely matches the position angle of the 20'' radio/optical/X-ray jet. In addition, the nucleus contains a significant structure of lower brightness at approximately the same position angle, although no counterjet is observed. By invoking relativistic beaming in order to enhance the jet and diminish the counterjet, it is shown that the jet must be aligned within about 60 degrees to our line of sight, and its flow velocity must exceed about 60% of the speed of light. The knots embedded in the 20'' jet contain no bright compact structures, and the sizes of the innermost knot (knot D) is between 0.1-0.3''.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 263
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  • 83
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    Model calculations of the molecular composition of interstellar grain mantles (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A chemical reaction scheme comprising gas phase as well as grain surface reactions is used for the numerical calculation of the chemical composition of mantles accreting on interstellar grains. The composition of the growing grain mantle is determined on the basis of the relative accretion rates of the gas phase molecules and diffusion-controlled surface reactions. Results show that grain mantles generally consist of the molecules H2O, H2CO, N2, O2, CO, CO2, H2O2, and NH3. A detailed examination of the formation of H2 on grain surfaces leads to the conclusion that it proceeds through hydrogen abstraction from such molecules as H2CO, H2S, N2H2, and N2H4. The IR characteristics of the calculated grain mantles are discussed with emphasis on the observed ice band at the 3250/cm wavelength.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 114; 2, Oc; Oct. 198
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  • 84
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    International Ultraviolet Explorer observations of the R Aquarii jet (1982)
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    Publication Date: 2011-08-18
    Description: Ultraviolet spectra were obtained with the International Ultraviolet Explorer of the newly discovered optical-radio jet feature in the symbiotic variable R Aquarii. The far-UV continuum of the jet is characterized by strong continuum which rises with decreasing wavelength in the 1200-2000 A wavelength range and is considerably different in appearance from the relatively flat continuum exhibited by ionized nebulosity in the central star. Prominent Si III semi-forbidden lines and Si II emission lines seen in the central region are virtually absent in the jet. This could reflect the depletion of silicon in the feature, the result of grain formation in material that has been ejected by the central star. Consistent with this interpretation is the overall excitation of the jet that suggests it is cooler than the nebulosity that engulfs the central UV object.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 262
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  • 85
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    The mid-ultraviolet spectrum of Epsilon Aurigae (1982)
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    Publication Date: 2011-08-18
    Description: An LTE synthetic spectrum with Te = 7800 K and log g = 1 has been computed for the 2455-to-3230 A range of Epsilon Aurigae (F0 1a). This has been compared with the spectra observed with 0.2 A resolution with the IUE experiment and with 0.1 A resolution with the BUSS experiment. As a consequence of this comparison, identifications and abundance values have been obtained. Ions definitely present include Mg I, Mg II, Al I, Al II, Si I, Ca II, Ti II, V II, Cr II, Mn II, Fe I, Fe II, Co II, Ni I, Ni II, Zr II. Ions which are possibly present include Ti III, Mn I, Fe III, Nb II, Mo I. The abundances are nearly 10 times the solar values for the iron group, with the exception of Fe, which has solar abundance. The abundances of the other elements are solar.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics Supplement Series; 50; Nov. 198
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  • 86
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    The Halley dust model (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The properties of dust ejecta from Comet Halley are studied on the basis of (a) evidence from the comet's past apparitions and (b) analogy with recent, physically similar comets. Specifically discussed are the light curve and spectrum, discrete phenomena in the head, the physical properties of the nucleus (size, albedo, rotation, surface temperature, and morphology), and an interaction between the nucleus and dust atmosphere. Also reviewed are constraints on the size and mass distributions of dust particles, information on submicron-size and submillimeter-size grains from the comet's dust tail and antitail, and the apparent existence of more than one particle type. Similarities between the jet patterns of Halley and the parent comet of the Perseid meteor stream are depicted, and effects of the surface heterogeneity (discrete active regions) on the dust flow are assessed. Current dust models for Halley are summarized and the existence of short-term variations in the dust content in the comet's atmosphere is suggested.
    Keywords: ASTROPHYSICS
    Type: (ISSN 0273-1177)
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  • 87
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    The UV stellar classification program (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The UV stellar classification program based on IUE data, its rationale, and its status, are described. The program provides sequences of calibrated spectra covering all spectral types.
    Keywords: ASTROPHYSICS
    Type: ESA 3rd European IUE Conf.; p 327-330
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  • 88
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    The early-type component in v1 Sagittarii (1982)
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    Publication Date: 2011-08-18
    Description: Four low-resolution UV spectra of v1 Sgr (cK2) were obtained with the IUE satellite to investigate the nature of the hot component in this object, which was detected in the Astronomical Netherlands Satellite UV photometric data. The IUE results show that the spectral energy distribution of v1 Sgr in the FUV is comparable to that of a B9 star. FUV flux level, when compared with that of the mid-ultraviolet flux level, indicates that the luminosity of the hot component is roughly equivalent to that of a main-sequence star, assuming that the mid-ultraviolet flux is dominated almost entirely by a K2 I object. No discernible spectral features are present in the FUV, contrary to what may be expected in a star of B9 spectral type. Two possible interpretations are suggested: the hot component is a rapidly rotating star, or an accretion disk surrounding a central object which could be a collapsed star is being observed.
    Keywords: ASTROPHYSICS
    Type: Astronomical Society of the Pacific; vol. 94
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  • 89
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    Response of a Doppler canceling system to plane gravitational waves (1982)
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    Publication Date: 2011-08-18
    Description: This paper discusses the interaction of long periodic gravitational waves with a three-link microwave system known as the Doppler canceling system. This system, which was developed for a gravitational red-shift experiment, uses one-way and two-way Doppler information to construct the beat signal of two reference oscillators moving with respect to each other. The geometric-optics approximation is used to derive the frequency shift produced on a light signal propagating in a gravitational-wave space-time. The signature left on the Doppler-cancelled beat by bursts and continuous gravitational waves is analyzed. A comparison is made between the response to gravitational waves of the Doppler canceling system and that of a (NASA) Doppler tracking system which employs two-way, round-trip radio waves. A threefold repetition of the gravitational wave form is found to be a common feature of the response functions of both systems. These two functions otherwise exhibit interesting differences.
    Keywords: ASTROPHYSICS
    Type: Physical Review D - Particles and Fields; vol. 26
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  • 90
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    Improved perfect-fluid energy-momentum tensor with spin in Einstein-Cartan space-time (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The description of the spin given here is classical in that it is intrinsic but not quantized. The approach in this matter is similar to, for example, the work of Bailey and Israel (1973, 1975, 1979), where the fluid particles, which have intrinsic spin, may be galaxies or clusters of galaxies. The elementary particles of these objects and the 'ferromagnetic alignment' of their quantum spins are not resorted to in order to describe a fluid with spin. Physically this means that the equation of motion for the spin tensor is a modified Fermi-Walker transport equation (Misner et al., 1973), arising as a direct result of the inclusion of spin as an intrinsic variable in the thermodynamic description of the internal energy. The variables in this description are classical variables throughout and are not microscopic fields. An improved perfect-fluid energy-momentum tensor that includes spin and torsion is presented. Use is made of a Lagrangian variational principle based on the tetrad formalism of Halbwach (1960) and the method od constraints of Ray (1972).
    Keywords: ASTROPHYSICS
    Type: Physical Review Letters; 49; Oct. 11
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  • 91
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    A survey of interstellar neutral potassium. I - Abundances and physical conditions in clouds toward 188 early-type stars (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Observations of interstellar absorption in the resonance doublet 7664, 7698 A of neutral potassium toward 188 early-type stars at a spectral resolution of 8 km/s are reported. The 7664 A line is successfully separated from nearly coincident telluric O2 absorption for all but a few of the 165 stars for which K I absorption is detected, making possible an abundance analysis by the doublet ratio method. The relationships between the potassium abundances and other atomic abundances, the abundance of molecular hydrogen, and interstellar reddening are investigated.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal Supplement Series; 50; Oct. 198
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  • 92
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    The energetic molecular outflow near AFGL 961 - Millimeter-wave and infrared observations (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Sensitive millimeter-wave C-12O line observations and near-infrared hydrogen recombination line observations of AFGL 961 are reported and analyzed. The observations show that the high-velocity flow has a maximum extent of at least six arcmin or 1.9 pc at the distance of AFGL 961. The flow is anisotropic and the emission profiles are asymmetric in velocity. The mass of the gas involved in the flow is determined to be approximately 19 solar masses, and the kinetic energy of this gas is estimated to be about 8 x 10 to the 46th ergs. These observations are interpreted as evidence that an energetic bipolar outflow of molecular gas is occurring near AFGL 961. Comparison of infrared recombination line data, radio continuum, and CO observations shows that a strong, ionized, stellar wind would not be a sufficient force to drive the outflow. The effects of the outflow on the surrounding molecular cloud was also investigated.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 261
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  • 93
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    Ab initio calculation of infrared intensities for the linear isoelectronic series HCN, HNC, CO, HCO/+/, and HOC/+/ (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Ab initio infrared intensities and dipole moment derivatives expressed in atomic polar tensor form are calculated using the 4-31 and 6-31G(double asterisk) basis sets for the isoelectronic HCN, HNC, CO, HCO(+), and HOC(+) series of molecules. The calculated atomic polar tensors are analyzed in terms of the charge-charge flux-overlap model, which is found to be useful in explaining some of the trends observed in the dipole moment derivatives for this series of molecules. A detailed examination of the dipole moment derivatives for the structural isomers indicates some of the ways in which experimental atomic polar tensors for one isomer should be modified to predict infrared intensities for the other isomer. The absolute intensities calculated for the HCO(+) and HOC(+) ions are believed to be accurate to within a factor of 2 and thus should be useful in astrophysical applications.
    Keywords: ASTROPHYSICS
    Type: Journal of Chemical Physics; 77; Oct. 1
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  • 94
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    The detection of interstellar C I in the immediate vicinity of the sun (1982)
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    Publication Date: 2011-08-18
    Description: Multiple stacked IUE spectra reveal the presence of interstellar C I 1657 in the trough of a corresponding photospheric feature in the nearby star, Alpha PsA (d = 7 pc). This represents the first detection of this neutral atom in the interstellar medium within the immediate vicinity of the sun. It is suggested that C I may be a much better diagnostic tool in studying the local interstellar medium than the neutral species K I and Na I, which are observable at visual wavelengths. Variations in C I column density, coupled with b-values deduced from the Mg II doublet ratio, may prove to be an important means to unravel density and temperature fluctuations in the very local interstellar medium. Comparison of the line of sight toward Alpha PsA with previous Copernicus interstellar Mg II results for that of Alpha Leo tentatively indicates that the distribution of Mg II in the local cloud is not homogeneous about the sun. Rough constraints on the ionization fraction of hydrogen toward Alpha PsA do not conflict with previous data, implying that the very local interstellar medium is significantly ionized.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 260
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  • 95
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    Convective accretion disks and the onset of dwarf nova outbursts (1982)
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    Publication Date: 2011-08-18
    Description: Vertically integrated, steady state convective models of accretion disks have been constructed to explore the mechanism of instability in dwarf novae. The models and observations of dwarf novae suggest a picture in which transferred matter piles up in an optically thin torus. The torus eventually becomes optically thick, and the resulting convective structure is thermally unstable. Matter then flows inward, and the sudden conversion of gravitational potential energy to radiation is identified as the dwarf nova outburst. At sufficiently high mass accretion rates, the inflow is continuous.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 260
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  • 96
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    Sulfur chemistry in dense interstellar clouds (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: A model is presented for the gas phase chemistry of molecules containing sulfur in dense interstellar clouds. The sulfur chemistry is different from that used in previous models as a result of an extensive search of the recent literature and the availability of new laboratory data. The changes have a significant effect on the calculated abundance of sulfur compounds. The linked chemistry of sulfur and oxygen in the present model requires a severe depletion of sulfur and low fractional abundances of both O and O2 in the dense clouds. In contrast, the high abundance of SO and the low abundance of CS relative to SO in the HVS in the KL may indicate an oxygen-rich, high temperature environment compared to OMC-1. The formation of S-H bonds is slow because of the absence of radiative association between S(+) and H2. The present model underestimates the abundance of H2S unless a radiative association reaction between HS(+) and H2 is postulated.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 260
    Format: text
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  • 97
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    Gamma-ray spectroscopy of the galactic center region - Confirmation of the time variability of the positron annihilation line (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-27199)
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 260
    Format: text
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  • 98
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    Unknown
    Molecules in celestial objects. III - Study of CO in interstellar diffuse clouds (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The absorption lines corresponding to the A-X transition of CO have been looked for in the IUE spectra of 14 stars with varying values of the colour excess, E(B-V) and found to be present in the spectra of nine stars with E(B-V) at least 0.28. The column density of CO has been determined towards these nine stars and its upper limit towards the rest of the stars. The curve of growth analysis has been found to show that the contribution to CO absorption is possibly from a single interstellar cloud for stars with E(B-V) less than 0.4 and from more than one cloud for stars with E(B-V) greater than 0.4. The observed column density of CO as a function of E(B-V) has been found to be in good agreement with that expected from the theory of ion-molecular chemistry.
    Keywords: ASTROPHYSICS
    Type: Royal Astronomical Society; vol. 200
    Format: text
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  • 99
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    Astrophysical tests for radiative decay of neutrinos and fundamental physics implications (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-20098)
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 257
    Format: text
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  • 100
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    Unknown
    The case for anisotropic mass loss from T Tauri stars (1982)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Observational evidence and theoretical arguments are assembled in favor of directed, rather than isotropic, mass flows from T Tauri stars. These arguments include the structure of T Tauri nebulosities, radio continuum maps of the stars, the motions of Herbig-Haro objects away from their exciting T Tauri stars, bipolar CO flows, and particularly the spatial coincidence of an optical jet and radio emission associated with an embedded, probably T Tauri star in the dark cloud L1551.
    Keywords: ASTROPHYSICS
    Type: Astronomical Society of the Pacific; vol. 94
    Format: text
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