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IUE observations of V1331 Cyg.
Mundt, R.; Appenzeller, I.; Chavarria, C. +2 more
Low dispersion IUE spectrograms (at wavelengths of 2200-3200 A) of the unusual T Tauri star V 1331 Cyg have been obtained. The observed UV flux is consistent with the assumption that V 1331 Cyg has a photosphere corresponding to a spectral type near F 0. As in the blue to red spectral range, the observed UV line spectrum (dominated by very strong …
Ultraviolet Observations of the X-Ray Sources in the Eta-Carinae Nebula
Macchetto, F.; Viotti, R.; Cassatella, A. +1 more
η Car is surrounded by a dense nebula ejected during the last 150 years. The Einstein satellite recently detected intense X-ray emission from η Car and its nebula indicating the existence of efficient gas heating processes. Ultraviolet observations with IUE confirmed the presence of hot gas in the condensation S of the nebula and in η Car. Possibl…
Low-Latitude Galactic γ -ray Emission: A Probe, not a Proof
Bignami, G. F.
The emission of high energy (above 70 MeV) γ -rays from the galactic disc has been mapped by the COS-B mission with unprecedented detail. The results for |b| < 15 degrees are seen to contain evidence of structures correlated with the Galaxy on various scales, from the `grand design' down to granularities, showing that the diffuse interstellar m…
An Optical Outburst from the Periodic Recurrent X-Ray Transient A0538-66
Charles, P. A.; Willis, A. J.; Thorstensen, J. R. +2 more
We present optical spectroscopy and photometry and IUE spectroscopy of the counterpart of the LMC recurrent X-ray transient A0538-66 during an outburst at the end of December 1980 which was consistent with the 16.6 day X-ray period (Skinner, 1980). The optical spectra show steadily increasing Balmer and HeI emission (indicative of a shell phase) s…
The far-ultraviolet energy distribution of two globular cluster blue horizontal-branch stars in M 13.
de Boer, K. S.; Code, A. D.
The far-UV energy distribution of two blue horizontal-branch (BHB) stars detected in the nucleus of M13 is presented. Their continua can be characterized by a model atmosphere of an effective temperature of 15,000 to 20,000 K and log g = 4.5, and it follows that V is in the range 15.9-16.7 for these stars. Comparison with integrated photometry by …
UV observation of the nucleus of NGC 3077.
Galletta, G.; Benacchio, L.
Spectroscopic observations in the range 1200-2000 A of the Ir II galaxy NGC 3077 made with the IUE telescope using the large aperture (10 arcsec x 20 arcsec) slit in low-dispersion mode are presented. The observations show the presence of a hot stellar component (20,000-23,000 K) spatially distributed in an asymmetric way. Analysis of the slit pos…
On the nature of the 125 day cepheid V810 CEN (=HR 4511) : IUE spectra.
Pakull, M.; van Genderen, A. M.; Heck, A. +4 more
Low and high resolution IUE spectra of the possible extremely long-period, low-amplitude classical Cepheid V 810 Cen (equals HR 4511), are analyzed to determine the effects of its hot blue companion on the observed optical light - and radial velocity - curves. From these spectra we conclude that the early B - type companion is hardly detectable in…
Ultraviolet observations of two extreme population II stars : detection of chromospheric emission and mass loss.
Spite, M.; Caloi, V.; Spite, F.
We describe some spectroscopic features in the ultraviolet and visible ranges for two extreme Population II stars. These features can be interpreted as indicating mass loss.
Far-ultraviolet energy distributions of the metal-poor A stars HD 109995 and HD 161817.
Boehm-Vitense, E.
Low-resolution IUE spectra at wavelengths between 1300 and 3400 A of the metal-poor stars HD 109995 (A1p) and HD 161817 (A4p) have been compared with model-atmosphere energy distributions computed by Kurucz (1979). Good overall agreement is found. Effective temperatures, metal abundances, and angular diameters could be determined. Assuming an abso…
The ultraviolet spectrum of the eclipsing binary ZET Aur.
Hack, M.
The ultraviolet spectrum of the atmospheric binary Zeta Aur has been observed with the IUE, in the high resolution mode, at the 0.91 and 0.27 spectrum phases. The phases were computed from the epoch minimum light, using the epoch and period given by Kukarkin et al. (1969), and from the periastron passage, using the epoch given by Wright (1970). Th…