Search Publications
Variable mass flux in the Be star 59 Cyg.
Doazan, V.; Thomas, R. N.; Kuhi, L. V.
The paper reports observations of 59 Cygni (B1.5 Ve) made in 1978 December with IUE at high resolution simultaneously with visual spectral observations. The C IV and probably the N V resonance absorption lines show whole-line violet displacements of 750 km/s, exceeding the photospheric escape velocity. Si IV and lesser ions show violet displacemen…
Absolute ultraviolet spectrophotometry with the TD-1 satellite. XI.
Beeckmans, F.; Hubert-Delplace, A. M.
Low resolution S 2/68 observations are used to show that Be stars of spectral type B0-B5 have a deficiency of ultraviolet radiation (at 2100 A) as compared to the visible with respect to normal stars of the same spectral type. The deficiency is statistically correlated with the strength of visual emission lines, with the existence of an infrared e…
IUE ultraviolet spectroscopy of stars in the Magellanic Clouds.
Hutchings, J. B.
Low dispersion IUE spectra of seven hot supergiants in the Large Magellanic Cloud and one in the Small Magellanic Cloud are presented. Stellar winds are present in all the stars, but the resonance lines have weak or no emission and probably have lower terminal velocities than galactic counterparts. Spectral energy distributions are used to derive …
The extinction of HD 200775 by dust in NGC 7023.
Witt, A. N.; Yang, S.; Walker, G. A. H. +1 more
The extinction properties of the Be shell star HD 200775 caused by dust in the bright reflection nebula NGC 7023 are discussed on the basis of direct observations of HD 200775. Reddening curves obtained between 5500 and 6800 A by a Reticon linear array are found to differ from any simple curve, lacking diffuse interstellar features except at 6284 …
Resonance line profiles in A type supergiants from IUE and Copernicus spectra.
Talavera, A.; Lamers, H. J. G. L. M.; Praderie, F.
A comparative study of UV resonance line profiles in one F0 type and four A type supergiants is made from a set of IUE spectra; the O I, C I, C II, Mg II, Al II, Al III, Si II, P II and Fe II ions are considered. Alpha Cyg (A 2 Ia) shows the most prominent velocity field effects on the profiles: they are broadened, asymmetric and shifted up to 240…
IUE observations of RW Hya (gM2+pec).
Kafatos, M.; Michalitsianos, A. G.; Hobbs, R. W.
Analysis of the intense UV continuum observed between 1100 and 2000 A suggested that observations of the late type star RW Hya is a binary system in which the secondary is the central star of a planetary nebula. The UV spectrum is characterized by semiforbidden and allowed transition lines, of which the C IV doublet is particularly strong. Tidal i…
S I emission in EUV spectra of late-type stars.
Jordan, C.; Brown, A.
Observations of strong neutral sulfur emission lines in the EUV spectra of late-type giant and supergiant stars are discussed. Low- and high-resolution spectra of Alpha Tauri and Beta Gru are presented which demonstrate the contribution of the S I (UV 9) multiplet to the observed features at approximately 1296 A as well as the strong O I multiplet…
Interstellar C IV and SI IV column densities toward early-type stars.
Kondo, Y.; McCluskey, G. E.; Bruhweiler, F. C.
Equivalent widths and deduced column densities of Si IV and C IV are examined for 18 early-type close binaries, and physical processes responsible for the origin of these ions in the interstellar medium are investigated. The available C IV/Si IV column density ratios typically lie within a narrow range from 0.8 to 4.5, and there is evidence that t…
34.1 day periodicity in CYG X-3
Molteni, D.; Robba, N. R.; Scarsi, L. +1 more
COS-B observations of a 34.1-day periodicity in the X-ray intensity of the X-ray source Cyg X-3 are discussed. Collimated proportional counter observations of the source were made in the 2-12 keV energy range for a total of approximately 100 days in three intervals of approximately one month each; data from two of these intervals allow the monitor…
An absorption line in the ultraviolet spectrum of 40 ERI B.
Greenstein, J. L.
Two excellent low-resolution spectra show an absorption line of equivalent width 3 A, near 1391 A, in the typical DA (hydrogen atmosphere) white dwarf 40 Eri B. The line is confirmed by a high-resolution spectrum and is the first seen in any DA star. Ultraviolet fluxes and the profile of Lyman-alpha confirm an effective temperature near 17,000 K. …