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EXO 023432-5232.3 - an eclipsing AM Herculis binary.
Cropper, Mark; Bailey, Jeremy; Hough, J. H. +1 more
The authors report observations of the serendipitous EXOSAT source EXO 023432-5232.3 which confirm that the object is an AM Herculis type binary and show the presence of eclipses by the companion star. From high-speed photometry of the eclipses they deduce that the cyclotron emission region is less than one seventh the size of the white dwarf. Fro…
The Nature of TT Hydrae
Etzel, Paul B.
Photometric solutions are made of previously published photoelectric light curves of TT Hydrae. The WINK model is employed to give radii of rA = 0.0894 and rB = 0.2431, and an orbital inclination of i = 84.4 deg. Spectrophotometry is presented and analyzed to give revised spectral types of B9.5 V and phase-variable G9 to K1 I…
Spectrophotometry and Chemical Composition of the Oxygen-poor Bipolar Nebula NGC 6164--5
Dufour, Reginald J.; Parker, Robert A. R.; Henize, Karl G.
The paper presents new ground-based and IUE spectrophotometry of several positions in NGC 6164-5 surrounding the Population I Of star HD 148937. Electron temperatures, densities, and abundances are derived for the various positions in the nebula using spectral line information. For all of the regions observed, Ne/H is depleted by an amount compara…
A White Dwarf Companion to the Main-Sequence Star 4 O 1 Orionis and the Binary Hypothesis for the Origin of Peculiar Red Giants
Johnson, Hollis R.; Ake, Thomas B.
In the course of an investigation with the IUE satellite of the ultraviolet spectra of peculiar red giants, the authors have discovered a white dwarf companion to the MS star 4 ο1Ori. They discuss the reductions performed for the ο1Ori IUE observations, and compare these with field white dwarfs to derive parameters of the whi…
High-resolution spectroscopy of central stars of planetary nebulae : LSS 1362.
Werner, K.; Heber, U.; Drilling, J. S.
High resolution spectra of the hot sdO star LSS 1362, a central star of a planetary nebula, are analyzed by means of model atmosphere techniques. Improved NLTE model atmospheres based on the newly developed 'accelerated lambda iteration' method are used. The very high effective temperature (100000 K) derived previously from the UV energy distribut…
The recurrence behaviour of X-ray bursts from 4U/MXB 1735-44.
van Paradijs, J.; Lewin, W. H. G.; Sztajno, M. +2 more
During about 80 h of uninterrupted observations of the X-ray burst source 4 U/MXB 1735-44, made in August 1985 with Exosat, five bursts were observed. The bursts occur at irregular intervals, ranging between 30 min and 36 h. The burst sizes do not scale with the intervals preceding the bursts; in particular the energy in a burst which occurred aft…
IUE observations of high galactic latitude F supergiants HD 161796 and HD 187885.
Pottasch, S. R.; Wamsteker, W.; Parthasarathy, M.
Low resolution (6 A) IUE ultraviolet spectra of the high galactic latitude F supergiants HD 161796 (F3 Ib) and HD 187885 (F2-3I) are analyzed. The UV spectrum (1250 A to 3250 A) of HD 161796 shows no excess UV flux attributable to a hot degenerate companion. From the UV spectrum the temperature is found to be 6300 K. There is no evidence for signi…
The High-Resolution Soft X-Ray Spectrum of HZ 43. II. Bolometric X-Ray Flux, Effective Temperature, and Radius
Heise, J.; Bleeker, J. A. M.; Brinkman, A. C. +1 more
The authors present a reanalysis of the high-resolution soft X-ray spectrum of HZ 43, obtained with the 500 lines mm-1 transmission grating spectrometer on EXOSAT. They show here that the estimates of Te and log g from the shape of the X-ray spectrum depend critically on the code used to generate the model spectra, but that t…
Far-ultraviolet and X-ray emission of the long period RS CVn star sigma Geminorum.
Linsky, J. L.; Kjeldseth-Moe, O.; Westergaard, N. J. +6 more
The new UV and X-ray observations of σ Gem support the theory that large active regions associated with starspots are responsible for the enhanced line emission commonly seen in RS CVn systems. The rotational modulation of the UV line fluxes increases with temperature of the line-forming region. The X-ray emission from the stellar corona, on the o…
Quasi-periodic oscillations in the bright galactic bulge X-ray sourceGX 340+0.
van Paradijs, J.; van der Klis, M.; Lewin, W. H. G. +4 more
Quasi-periodic oscillations (QPOs) have been detected in the X-ray flux of the bright Galactic bulge X-ray source GX 340+0. The QPO, the associated red noise, and their relation to the spectral state of the source are described. The QPO behavior is found to be similar to that seen in Cyg X-2 and GX 5-1.