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MG II Line Profiles of the Mira S Carinae
Brown, Alexander; Bookbinder, Jay A.; Brugel, Edward W.
A series of high-dispersion IUE observations obtained to investigate the evolution of the shock structure of the Mira variable S Carinae have produced (despite limited phase coverage) a set of five exceptionally interesting spectra of the Mg II h and k lines. The two primary findings of these observations are (1) there is significant emission from…
Far-Ultraviolet Spectrophotometry of SPICA
Snow, Theodore P.; Cook, Timothy A.; Cash, Webster
A spectrum of the star Spica (Alpha Virginis) from 960 to 1270 A was recorded by a rocket-borne spectrograph March 13, 1988. The spectrum, which has 3.4 A resolution, shows a much sharper drop-off in intensity near 1050 A than similar measurements made by the Voyager UVS, but is in good agreement with the spectrum obtained by Brune et al. in a 197…
An Interpretation of the Line Profile Variations in the IUE Spectrum of the Wolf-Rayet Binary gamma 2 Velorum
Sahade, Jorge; Brandi, Estela; Ferrer, Osvaldo E.
An analysis of the variable profiles of the high-temperature resonance lines of Si IV in the IUE spectrum of gamma(2) Vel has made it possible to describe these profiles as a superposition of two different profiles, namely, a P Cygni profile that remains practically stationary throughout the orbital cycle and an absorption profile that moves back …
Interstellar Gas and Large Grains toward HD 38087
Snow, Theodore P.; Witt, Adolf
High-dispersion IUE spectra have been obtained of HD 38087, a star associated with reflection nebulosity where 2175 A scattering has previously been observed. The presence of 2175 A in emission implies unusually large grains, an attempt was made to see how these unusual grains may have affected the depletions of gas-phase elements onto dust in the…
Terminal Velocity of Wind, Mass Loss, and Absorption Lines in the Central Star of the Planetary Nebula 75 +35 1
Feibelman, Walter A.; Bruhweiler, Frederick C.
The high-galactic latitude planetary nebula 75 + 35.1 deg was observed in the high-dispersion mode of the International Ultraviolet Explorer (IUE) satellite in the wavelength range 1150-1950 A. The N V resonance doublet at 1240 A and O V subordinate line at 1371 A exhibit strong stellar P Cygni profiles with absorption extending to -2150 km/s and …
Model Atmospheres and Parameters of Central Stars of Planetary Nebulae
Patriarchi, P.; Perinotto, M.; Cerruti-Sola, M.
Non-LTE hydrogen and helium model atmospheres have been obtained for temperatures and gravities relevant to the central stars of planetary nebulae. Low-resolution and high-resolution observations obtained by the IUE satellite have been used along with optical data to determine Zanstra temperatures of the central stars of NGC 1535, NGC 6210, NGC 70…
The Accretion Wake of 31 Cygni
Ahmad, I. A.
Archival IUE observations of 31 Cygni at phases at which its sister Zeta Aurigae systems exhibit evidence of an accretion wake are discussed. The absence of absorption in Mg II can be explained by the phase at the specific times of observation. The detection of high-velocity absorption due to C IV but not N V implies a shock temperature lower than…
Gamma-Ray Emission in MeV--GeV Region from Cygnus X-3
Li, Ti-Pei; Wu, Mei
The analysis of the simultaneous X-ray and gamma-ray observations of Cygnus X-3 by the ESA satellite COS B indicates that there exists a negative correlation between intensities of 2-12 keV X-rays and 150-5000 MeV gamma rays of Cygnus X-3. A clear image of a gamma-ray source at the position of Cygnus X-3 is obtained from the spatial distribution o…
The Ultraviolet Variability of HD 45166 (qWR+B8 V): Evidence for Stellar Wind Radiative Instabilities
Stickland, D. J.; Howarth, Ian D.; Heap, S. R. +1 more
High-resolution IUE spectroscopy of the low-mass qWR star HD 45166, obtained at several epochs during 1980-1988, reveals a complex pattern of variability in its stellar wind emission lines, P Cygni profiles, and highly ionized photospheric absorption spectrum. The most intensive observations, obtained during a 36 hr continuous run in February 1988…
The Ultraviolet to Infrared Energy Distribution of the BL Lacertae Object PKS 0422+00 at Two Different Brightness Levels
Maraschi, L.; Tanzi, E. G.; Bouchet, P. +2 more
The BL Lacertae object PKS 0422+00 was observed with IUE (International Ultraviolet Explorer) on 1987 August 31-September 1, when the visual magnitude of the object was V = 16.2, and again ~ 4 months later (1988 Jan 10) during an active state (V = 15.6). Quasi-simultaneous optical to infrared observations allow deriving a detailed spectral flux di…