Search Publications
IUE observations of comet P/Crommelin (1983 n)
Keller, H. U.; Evans, A.; Wallis, M. K. +2 more
Comet P/Crommelin has always been a difficult object to observe because of both its intrinsic faintness and its poor location in northern skies at the time of maximum activity. Observations were attempted with the International Ultraviolet Explorer (IUE) over a seven week period starting five days after the comet had reached perihelion. The nature…
Remote Sensing of the Magnetic Moment of Uranus: Predictions for Voyager
Hill, T. W.; Dessler, A. J.
Power is supplied to a planet's magnetosphere from the kinetic energy of planetary spin and the energy flux of the impinging solar wind. A fraction of this power is available to drive numerous observable phenomena, such as polar auroras and planetary radio emissions. In this report our present understanding of these power transfer mechanisms is ap…
Images in the rocket ultraviolet : the initial helium abundance and distance modulus of the globular cluster M5 from photometry of horizontal-branch stars.
Bohlin, R. C.; Stecher, T. P.; Cornett, R. H. +2 more
A natural laboratory for the study of postmain-sequence evolution of low-mass (less than one solar mass) metal-poor stars is provided by globular clusters. These clusters are, therefore, a critical aid for developing an understanding of advanced stages of stellar evolution and of the chemical evolution of the Galaxy. Bohlin et al. (1983) have desc…
EXOSAT Observations of the Bright X-Ray Source GX9+1
Hasinger, G.; Sztajno, M.; Truemper, J. +1 more
We present the results of the spectral and timing analysis of an observation of GX9+1/4U1758-205 performed with the Medium Energy Experiment aboard EXOSAT. During our observation the source flux varied irregularly in time scales from minutes to hours. No periodic emission in the period range from 16 msec to 2000 sec was found with an upper limit o…
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…