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Spectral and temporal studies of various late-type stars
McHardy, I.; Mewe, R.; Brinkman, A. C. +2 more
The RS CVn stars Capella and σ2 CrB have been measured with EXOSAT in soft and medium X-rays for about 24 hours each and the less active late-type star Procyon for about 6.5 hours. In addition, the RS CVn star γ. And was twice observed about one month apart for a total of about 7 hours, with the ME and the LE in the photometer mode only…
Shock-heated gas in the I Per OB association.
Nandy, K.; McLachlan, A.
In response to a suggestion by Phillips & Gondhalekar (1981) that hotgas is receding from the I Per OB association with a velocity of ≡30 km s-1, the authors have examined the IUE high-dispersion spectra of stars in the association for blueshifted lines of interstellar C IV, Si IV and Al III. As a result, the high-velocity ions are …
The identification of H 2311+77 with HD 220140, a probable RS CVn star.
White, N. E.; Giommi, P.; Pravdo, S. H.
H2311+77, one of the bright soft X-ray sources in the sky originally detected with HEAO 1, has been identified in an EXOSAT imaging observation with a 7.7-mag late-type star, HD 220140. The X-ray luminosity and the optical characteristics of this star indicate that it is probably an RS CVn binary system.
An X-ray corona in SS Cygni?
Heise, J.; King, A. R.; Watson, M. G.
A recent model1 for the X-ray emission of non-magnetic cataclysmic variables suggests that most of the observed hard X-ray flux originates in a radiatively-cooling quasi-hydrostatic corona surrounding the white dwarf as it accretes from its companion. We present here some results from a ~7.5-h EXOSAT observation of the dwarf nova SS Cyg…
First Detection of an X-Ray Burst and a One-Hour Intensity Dip in 4U1323-62
van Paradijs, J.; van der Klis, M.; Jansen, F. +1 more
We report the results of a 1.4 104s observation of the region of 4U 1323-62 with the EXOSAT ME. The source has a flux of 7 8 10-11 erg/cm2s (2 10 keV) and a power-law spectrum with 1.1 < α < 1.8. During our observation, the source showed a symmetric 60% dip in its X-ray flux of R~1 hr. The spectrum hardens du…
Galactic Supernova Remnants
Aschenbach, B.
A progress report is given on our current interpretation of the X-ray emission from supernova remnants. Previous results from earlier experiments, the Einstein Observatory in particular, are reviewed and supplemented by the most recent data from the Exosat mission for a selection of remnants (Puppis-A, Cas-A, SN 1006, RCW103, W49B). Major improvem…
Ultraviolet observations of the central star in the planetary nebula 136+5 1.
Heckathorn, J. N.; Fesen, R. A.
Ultraviolet spectra obtained with IUE are presented which confirm the Heckathorn et al. (1982) stellar candidate as the central star of the recently discovered planetary nebula 136+5°1. Spectra of the star covering the 1200 - 2000 Å range show a featureless continuum indicative of a black body temperature between 50,000 and 60,000K. Anomalously lo…
Chromospherically active stars. I. HD 136905.
Fekel, F. C.; Africano, J. L.; Quigley, R. +3 more
The variable star HD 136905, recently designated GX Librae, is a chromospherically active K1 III single-lined spectroscopic binary with a period of 11.1345 days. It has moderate strength Ca II H and K and ultraviolet emission features, while Hα is strongly in absorption. The inclination of the systems is 58°±17° and the unseen secondary is most li…
Interstellar reddeningh law towards the nucleus of H Per.
Franco, M. L.; Stalio, R.; Magazzu, A.
The extinction curves in the direction of four early-B main-sequence stars located in the nucleus of h Per (BD + 56 deg 501, BD + 56 deg 510, BD + 56 deg 516 and BD + 56 deg 517) and compared to one another and to the extinction curves derived from eight stars located in the same general area but lying at different distances. Data from UBV photome…
IUE high-resolution observations of Mira B.
Reimers, D.; Stickland, D. J.; Cassatella, A. +2 more
A high-resolution spectrum of Mira obtained with IUE on 1983 July 7 confirms the presence of broad emission lines with typical half base widths of ≅300 to roughly 1000 km s-1. No narrow emission lines are detected. The observed broad lines cannot originate from the extended atmosphere of the cool giant variable. The authors show in part…