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IUE observations of RCB stars during extinction minima.
Evans, A.; Whittet, D. C. B.; Bode, M. F. +2 more
The R Coronae Borealis stars RY Sgr and MV Sgr have been observed with the long-wavelength (LWR) camera on the IUE satellite during deep extinction minima. The ultraviolet spectrum of RY Sgr showed a rich chromospheric spectrum, similar to that observed in the optical spectrum of this object during previous extinction episodes. Near-simultaneous o…
Gas and star content and spatial distribution in the giant extragalactic H II region TOL 89.
Boksenberg, A.; Durret, F.; Bergeron, J.
Tol 89 is a giant H II region 2.5 kpc in diameter, located in one of the arms of the spiral galaxy NGC 5398. We have observed this object in the Uv with the International Ultraviolet Explorer, and at optical wavelengths with long slit spectrophotometric equipment. The UV spectrum of Tol 89 reveals P Cygni profiles, characteristic of stars with str…
High-dispersion ultraviolet spectra of the peculiar star RX Puppis.
Kafatos, M.; Michalitsianos, A. G.; Fahey, R. P.
High spectral resolution observations of the peculiar star RX Puppis obtained with the International Ultraviolet Explorer suggest the presence of a complex gaseous ring system which surrounds an accreting hot secondary. The anomalous line intensity ratio of the C IV 1548, 1550 A doublet during the observations exceeded the optically thick limit, i…
A redetermination of the luminosity, distance, and reddening of beta Lyrae.
Plavec, M. J.; Dobias, J. J.
The authors have redetermined the distance to β Lyrae and found that it probably lies between 345 and 400 pc, with the most likely value being 370 pc. With the corresponding true distance modulus of 7.8 mag, they find that the eclipsing system of β Lyrae has a maximum absolute visual magnitude of -4.7 mag. Using Wilson's model, the authors conclud…
The ultraviolet spectra of active galaxies with weak optical Fe II lines.
Netzer, H.; Wamsteker, W.; Wills, B. J. +1 more
The authors have obtained simultaneous optical and IUE spectra of two Seyfert galaxies that show very weak optical Fe II lines: Mrk 290 and Mrk 915. IUE archival spectra of the radio galaxy 3C 390.3 are also compared with optical data obtained during the same year. Strong, distinct ultraviolet features are observed in the spectrum of Mrk 290. A fi…
UV and optical spectroscopy of OB stars in M 31 and M 33.
Bianchi, L.; Hutchings, J. B.; Massey, P.
IUE UV spectra and MMT blue spectra have been obtained for 'normal' OB supergiant stars in M31 and M33. The authors classify the stars as late O to early B. UV and visible fluxes yield consistent values for the effective temperature, bolometric magnitudes, and extinction for the stars. The UV resonance lines have very low outflow velocities compar…
Large Magellanic CLOUD-X-4 AO:538-66 and Surrounding X-Ray Sources Observed with EXOSAT
Pietsch, W.; Beuermann, K.; Pakull, M. +4 more
Repeated observations of LMC X-4 with EXOSAT were carried out in 1983/84 in order to study its 30.5 day cycle and to cover the expected outbursts of the recurrent LMC transient A0538-66. The latter source was inactive during our campaign although a variable circumstellar envelope was still present around the optical counterpart. At least ten furth…
Rotational modulation of chromospheric emission in cool giants and "hybrid" stars.
Stencel, R. E.; Mullan, D. J.; Brosius, J. W.
Archival data from the International Ultraviolet Explorer have been used to study temporal variations of the Mg II h and k emission lines in eight late-type giants. Evidence is presented that the variations are periodic in nature. It is argued that the periodicities can be interpreted in terms of rotation. It is found that the four fastest rotator…
Photometric variations of the irregular variable V348 Sgr.
Jones, D. H. P.; Manfroid, J.; Heck, A. +2 more
The authors report visual estimates and photometric observations in various wavelength ranges of the irregular variable V348 Sgr. They cover dramatic drops of brightness (from V ≈ 12.5 to ≈ 18) which occurred in 1972, 1973 and 1981 with a time scale much shorter than the characteristic time mentioned by previous observers. These deep minima are, t…
Ss-Cygni in Outburst and Quiescence
Heise, J.; King, A. R.; Watson, M. G.
EXOSAT has been used to carry out a series of observations of the dwarf nova SS Cygni covering both quiescent and outburst states which provide a detailed picture of its behaviour at X-ray wavelengths. These results provide strong support for a new coronal model for the X-ray emission from non-magnetic white dwarf systems.