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The masses of early-type stars in the galactic halo determined from ultraviolet resonance line profiles.
Dufton, P. L.; Keenan, F. P.
Terminal velocities for stellar winds in intermediate and high galactic latitude OB stars have been determined from high resolution IUE ultraviolet spectra. These velocities, together with previous estimates, have been used to deduce stellar masses which are found to be similar to those derived from conservative and non-conservative evolutionary t…
Ultraviolet analysis of the peculiar supergiant HD 112374 = HR 4912.
Bohm-Vitense, E.; Proffitt, C.
The ultraviolet energy distribution of the metal-poor supergiant HD 112374 is analyzed based on observations from the International Ultraviolet Explorer (IUE) satellite for the region between 1200 and 2000 A. A discontinuity was found in the UV spectra at 2600 A which confirmed the low-abundance of heavy elements found by Luck et al. (1983). Value…
NGC 3448 revisited : a combined optical, radio and UV investigation.
Casini, C.; Bertola, F.; Bettoni, D. +3 more
The present combined optical, radio, and UV observations are of the irregular galaxy NGC 3448. It interacts with a smaller spiral companion, UGC 6016, forming the peculiar system Arp 205. Rotation curves were constructed from the red lines of a KPNO spectrum and from VLA H I observations. Abnormal velocity features were detected, and are attribute…
Variable, optically thick, hot plasma observed in interacting binaries
Kondo, Y.; McCluskey, G. E.; Parsons, S. B.
We report recent International Ultraviolet Explorer (IUE) observations of two interacting binaries, R Arae and HD 207739. The ultraviolet spectra indicate the presence of optically-thick, variable hot plasma in those binary systems. These two binaries may belong to a class of binaries that are currently undergoing a rarely observed and probably sh…
Far and extreme-ultraviolet spectrophotometry of hot white dwarfs : prospects for the determination of the He/H ratio in DA stars.
Wesemael, F.; Green, R. F.; Liebert, J.
The various spectroscopic methods currently available to determine the He/H ratio in hot DA white dwarfs are compared and contrasted. The observation of the optical He II λ4686 line, as well as that of the λ1640 line with the low-dispersion IUE camera, can only be wsed to determine the helium abundance for log (He/H) > -3. Low-resolution (λ/Δλ …
Simultaneous IUE and ground-based observations of V923 Aquilae.
Ringuelet, A. E.; Rovira, M.; Sahade, J. +2 more
Simultaneous IUE and ground-based observations of V 923 Aquilae carried out in July 1981 are used to propose a model of the extended envelope of this Be star with a transition region relatively close to the star, where the highly ionized species would be formed. The shell photographic and ultraviolet lines of Fe II and the photographic lines of Ca…
IUE observations of RS CVn-like binary sigma Corona Borealis.
Tarafdar, S. P.; Agrawal, P. C.
High and low resolution IUE observations of the triple system sigma CrB are presented. The spectra show the presencee of chromospheric (O I, Si II, Mg II) and transition region lines (He II, C II, C IV) in emission. The surface fluxes of these lines are orders of magnitude higher than those observed in the sun but are comparable to their values in…
Anomalous C IV and SI IV resonance lines in 36 Lyncis.
Sadakane, K.
Anomalously strong resonance lines of C IV and Si IV are found in the UV spectrum of the chemically peculiar star 36 Lyncis. The C IV resonance lines near 1550 Å are not found in about 40 other middle or late B-type main-sequence stars. The C IV lines (Wλ ≡ 1.0 Å) are stronger than the Si IV lines (Wλ ≡ 0.7 Å) in 36 Lyn and s…
The discontinuity near 1600 A in the spectra of DA white dwarfs.
Wegner, G.
Ultraviolet spectroscopic observations of two relatively cool DA white dwarfs, L481 - 60 (= WD 1544 - 37) and BPM 1266 ( = WD 2105 - 82), with the International Ultraviolet Explorer (IUE) satellite show a strong drop in their spectral energy distributions below 1600 A. Published model atmospheres and thier visual spectra suggest that these two sta…
Comments on the ultraviolet spectrum of gamma 2 Velorum.
Sahade, J.; Kondo, Y.; McCluskey, G. E., Jr.
A table of spectral features, including narrow, very broad, and 'photospheric' lines, in the ultraviolet spectrum of the Wolf-Rayet binary gamma(2) Velorum is given together with radial velocities at phase 0.99. The very broad lines display P Cygni profiles. Ten weak absorption features are tentatively assigned to blends of numerous lines of Fe IV…