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A Multiwavelength Study of the Carlson-Henize Sample of Early-Type Galactic Extreme Emission-Line Stars
Feldman, P. D.; Shore, Steven N.; Brown, Douglas N. +3 more
A UV, optical, and radio study of nine early spectral type extreme emission-line Galactic stars from the Carlson and Henize (1979) sample is presented. He 3-407 and He 3-1482 appear to be analogs of the massive evolved B(e) and luminous blue variable stars of the Magellanic Clouds. The sample appears to be confined to a narrow range in spectral ty…
The Mass of the Classical Cepheid SU Cygni
Bolton, C. T.; Evans, Nancy Remage
Velocities of the companion of the classical Cepheid SU Cyg have been measured from 13 IUE high-dispersion spectra. Because the companion is itself a member of a short-period binary system, its short-period orbit and the orbital amplitude of the center of mass in the long-period system are determined from a triple system solution. The velocity amp…
Ionization in Nearby Interstellar Gas
Frisch, P. C.; York, D. G.; Fowler, J. R. +1 more
Due to dielectric recombination, neutral magnesium represents an important tracer for the warm low-density gas around the solar system. New Mg I 2852 absorption-line data from IUE are presented, including detections in a few stars within 40 pc of the sun. The absence of detectable Mg I in Alpha CMa and other stars sets limits on the combined size …
On the Spectrum and Field Strength of the Magnetic White Dwarf GD 229
Foltz, Craig B.; Schmidt, Gary D.; Latter, William B.
The broad-coverage optical spectrum obtained for the strongly polarized magnetic white dwarf GD 229 reveals additional as well as apparent changes in the locations of known absorption features; the latter are ostensibly due to star rotation in the decade since the last published spectrum. Since (1) the spectrum of magnetized hydrogen is not consis…
Ultraviolet and Optical Spectroscopy of NGC 5548 and the Nature of the Broad-Line Region
Peterson, Bradley M.; Reichert, Gail A.; Korista, Kirk T. +1 more
The structure of the broad-line region in NGC 5548 is investigated by analysis of the integrated flux and profile variations observed in optical and ultraviolet emission lines. It is shown that the observations do not appear to be consistent with models which identify the variable part of the emission lines with a simple rotating disk structure. T…
The Fe V/Fe VI ionization structure in WNE Wolf-Rayet winds.
Koenigsberger, G.
An analysis of the phase-dependent intensity variations of the Fe IV, V, and VI pseudocontinua in four WNE binary systems having different orbital separations is used to obtain information regarding the ionization and velocity structures of the wind of the WR component. The ratio of Fe VI/Fe V decreases in strength as a function of distance from t…
IUE Observations of Rapidly Rotating Low-Mass Stars in Young Clusters: The Relation between Chromospheric Activity and Rotation
Simon, Theodore
If the rapid spindown of low-mass stars immediately following their arrival on the ZAMS results from magnetic braking by coronal winds, an equally sharp decline in their chromospheric emission may be expected. To search for evidence of this effect, the IUE spacecraft was used to observe the chromospheric Mg II emission lines of G-M dwarfs in the n…
Plasma parameters near the Comet Halley bow shock
Coates, A. J.; Wilken, B.; Kessel, R. L. +2 more
Plasma data from the Johnstone Plasma Analyzer on Giotto are used in a Rankine-Hugoniot analysis of Comet Halley bow shocks. The shock normals are obtained and compared with models and other estimates. Proton bulk parameters from the Fast Ion Sensor inbound are analyzed, and water group densities from the Implanted Ion Sensor (IIS) are obtained wh…
Observations of SK -69 203 and the Interstellar Extinction Toward SN 1987A
Walborn, Nolan R.; Fitzpatrick, Edward L.
We have obtained optical and UV spectroscopic observations of the Large Magellanic Cloud (LMC) star Sk - 69^deg^ 203, which is located in the 30 Doradus region of the LMC, approximately 2.2 arcmin north of the position of SN 1987A. The optical data reveal Sk - 69^deg^ 203 to be a B0.7 Ia supergiant with a moderate nitrogen enhancement. The UV spec…
Ultraviolet Fe VII Absorption Lines in Planetary Nebula Nuclei, Hot Subdwarfs, and Hot Degenerate Objects
Feibelman, Walter A.; Bruhweiler, Frederick C.
Results are reported from a search for Fe VII absorption lines in data from high-dispersion IUE-SWP observations of PN nuclei (PNN), hot subdwarfs (HSDs), and hot white dwarfs (HWDs). The data-reduction techniques employed are outlined, and the results are presented in extensive tables and sample spectra and characterized in detail. Absorption in …