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Cepheid Companions? FM Aquilae, FN Aquilae, RX Aurigae, Y Lacertae, and RS Orionis
Evans, Nancy Remage; Szabados, Laszlo; Udalska, Joanna
IUE spectra have been used to search for companions of FN Aql and RX Aur, two classical Cepheids which have been tentatively identified as binary stars on the basis of cyclic variations in their pulsation periods. Three other Cepheids, FM Aql, Y Lac, and RS Ori, suspected of having blue companions from the (U-B), (B-V) diagram, have also been inve…
Differential Line Development and the Complex Structure of the Broad-Line Region in Fairall 9
Zheng, Wei; O'Brien, Paul T.
We find that the profiles of the UV emission lines Lyα, C IV λ1549, and Mg II λ2798, in the Seyfert 1 galaxy Fairall 9 vary such that the lines are broader when the object is brighter. The profile changes occur mainly near the line center for Lyα and C IV and in the wings for Mg II. These results indicate that the broad-line region (BLR) has a com…
The photospheric temperatures and composition of very hot He-rich white dwarfs.
Barstow, M. A.; Holberg, J. B.
Results are reported from a detailed analysis of Exosat observations of six hot He-rich white dwarfs belonging to, or related to, the spectroscopic subclass of PG1159 stars. These objects are thought to evolve directly from O VI type planetary nebulae nuclei and provide an important link in models of white dwarf evolution. When the Exosat data are…
Accretion behaviour in SS Cygni.
Gaudenzi, S.; Giovannelli, F.; Claudi, R. U. +1 more
The He II (1640 A) equivalent widths are determined from 28 IUE short wavelength low resolution spectra of SS Cygni in quiescence and in outburst. By using the boundary layer model for cataclysmic variables (Patterson and Raymond 1985), the mass accretion rate M(He II) is derived. This mass accretion rate is practically coincident with the rate of…
Coordinated observation of the massive system 4U 1700+24 = HD 154791.
Frontera, F.; Manzo, G.; Robba, N. R. +7 more
The authors report results from multifrequency observations of the X-ray source 4U 1700+24 / HD 154791. This source was observed simultaneously with the EXOSAT and IUE satellites on March 25, 1985, and it is continuously monitored in the optical band at the Bologna Astronomical Observatory since July 1984. Their observations show source features w…
The bimodal spectral and QPO-behaviour of GX 17+2.
Hasinger, G.; Truemper, J.; Langmeier, A.
The spectral and temporal analysis of Exosat observations of the bright galactic bulge source GX 17+2 is presented. The source shows a bimodal spectral and temporal behavior. High-frequency (24-28 Hz) quasi-periodic oscillations (QPO) are found on the horizontal branch of the H-I-diagram. There is evidence for a second harmonic at 50 Hz. QPOs with…
The Long Period Binary AL Velorum: The Atmospheric Eclipse of a Bright KO Giant
Shore, Steven N.; Kondo, Yoji; Eaton, Joel A. +1 more
The properties of the AL Vel binary system, a Zeta Aur system containing a B dwarf and a bright K0 giant, are reviewed with reference to IUE observations of its atmospheric eclipse and eclipse of the accretion disk around the B-dwarf component. It is found that the conditions in the chromosphere are rather similar to those in the Zeta Aur supergia…
EXOSAT observations of three DA white dwarfs.
Beuermann, K.; Giommi, P.; Koester, D. +3 more
Exosat broad band filter observations, optical and IUE spectra, are presented for three DA white dwarfs. One source is a previously known Hyades white dwarf, the other two are new DA detected by Exosat. The results are consistent with previous observations of other DA white dwarfs and indicate that an absorber other than hydrogen (most probably he…
Ultraviolet Observations of the Enigmatic Bipolar Nebula M1-92
Feibelman, Walter A.; Bruhweiler, Frederick C.
IUE observations of the bipolar nebula M1-92 indicate that this object is an evolved object and possibly a preplanetary nebula. Data acquired in the SWP camera clearly show a flat UV continuum indicative of a relatively unobscured O subdwarf. Data acquired in the long wavelength region of the SWP and in the LWP camera reveal an object which mimics…
Mesures de vitesses radiales. III. Accompagnement AU sol du programmed'observation du satellite Hipparcos. Mesure de la vitesse radiale de391 etoiles dans 12 champs.
Burnage, R.; Fehrenbach, Ch.
The radial velocities of 391 stars, obtained with the Fehrenbach objective prism associated to the Schmidt telescope of the Observatoire de Haute-Provence are presented. These stars belong to fields specially chosen for containing several Hipparcos input catalog star members. Each field is presented independently. The list includes HD and BD ident…