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The search for the elusive companion of EG Andromedae.
Pesce, Joseph E.; Stencel, Robert E.; Oliversen, Nancy A.
The authors report observations at opposite quadratures of the interacting symbiotic binary EG And (HD 4174, Period = 470d). After correcting for absolute motion at the system, it appears, surprisingly, that many of the nebular lines arise from material that moves with the red giant star. This fact is used to interpret the observed comp…
Continuum Distributions and Line Profiles of Ux-Ursae Type Nova like Systems
Haug, K.
Combined UV, optical and, in part, IR continuum distributions of the UX UMa-systems CPD-48°1577, V3885 Sgr, RW Sex and of the recently discovered cataclysmic system PHL 227 were determined from multi-wavelength spectroscopic and photometric data to search for general characteristics of these systems. The observed variations of the UV to IR spectro…
Rapid Variability of P Cygni Lines in Massive X-Ray Binaries
Voit, G. Mark; Kallman, Timothy R.; McCray, Richard
In early-type X-ray binaries, the recombination time scales for ions such as C IV, Si IV, and N V in the stellar winds of their massive OB companion stars can be very short compared to typical X-ray pulsation or fluctuation time scales. Thus, the authors predict that the 'bleached zones', in which these ions are removed from the stellar wind by X-…
A Nonspherically Symmetric Model for the Peculiar A Star Alpha 2 CVn
Bohm-Vitense, Erika; van Dyk, Schuyler D.
Observations show that in the optical region the peculiar A star α2CVn has a flatter energy distribution during maximum light than during minimum light. This indicates that during maximum light we see a lower-temperature region, but necessarily larger surface area, than during minimum light. This suggests a nonspherically symmetric star…
The third spectrum of erbium in HR 465.
Cowley, Charles R.; Greenberg, Marcella
The strong presence of Er III in coude spectra of the chemically peculiar (CP) A star HR 465 at the time of rare-earth maximum is discussed. Er III is surely present in other CP stars; earlier studies are confirmed. Er III is only a marginal detection on IUE images of HR 465. A very crude abundance calculation, using an assumed oscillator strength…
A Flare Event on the Long-Period RS Canum Venaticorum System IM Pegasi
Huenemoerder, David P.; Buzasi, Derek L.; Ramsey, Lawrence W.
The characteristics of a flare event detected on the long-period RS CVn system IM Pegasi are reported. The low-resolution spectrum show enhancements of up to a factor of five in some emission lines. All of the ultraviolet emission lines normally visible are enhanced significantly more than the normal 30 rotational modulation. Emission fluxes of bo…
Low-Mass X-Ray Binaries in the Large Magellanic Cloud
Beuermann, K.; Bianchi, L.; Pakull, M. W. +1 more
We report results on three low-mass X-ray binaries (LMXB) in the LMC, obtained with EXOSAT, IUE and ground-based (ESO) telescopes: LMC X-2 which appears to be "Sco X-1"-like, LHG 83 and LHG 87. The latter are two weaker sources first detected in the course of the HEAO-B LMC survey. They have faint optical counterparts of which LHG 87 was only rece…
An IUE Survey of Activity in Red Giants and Supergiants
Gibson, D. M.; Oznovich, I.
Chromospheric and transition region line activity is examined in apparently single red giants and supergiants using the IUE archives. Low-resolution, large-aperture spectra (mostly short-wavelength) were used to search for variations of emission-line fluxes in time. A series of automatic processing procedures were implemented in order to uniformly…
Detailed Analysis of a Surface Feature on Comet p/ Halley
Wilhelm, K.; Keller, H. U.; Schwarz, G. +9 more
The surface of the nucleus of comet P/Halley is visible on many images taken by the Halley Multicolour Camera on board the Giotto spacecraft. A number of structural features like "mountains" or "surface dips" are clearly discernible. This paper outlines the methods that can be applied to analyze a surface feature with the aim of obtaining its char…
The rapidly oscillating AP stars as a test of stellar chromospheric heating mechanisms.
Sonneborn, G.; Shore, S. N.; Brown, D. N. +1 more
The discovery of a new class of magnetic stars, the rapidly pulsating Ap stars, provides an unprecedented tool for the study of Alfvénic heating in the outer atmospheres of main sequence stars. In this note, the authors point out that detection of rotationally modulated chromospheric emission line fluxes, especially the Ca II, Mg II, and C IV line…