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Simultaneous Hubble Space Telescope and ASCA Observations of LMC X-4: X-Ray Ionization Effects on a Stellar Wind
McCray, R.; Cheng, F. H.; Boroson, B. +2 more
We present first results from simultaneous ultraviolet (HST/GHRS) and X-ray (ASCA) observations of the 13.5 s pulsar LMC X-4, taken in 1996 May. The ASCA observations covered 1.12 binary orbits (1.58 days), and the Hubble Space Telescope observations were centered on this for roughly 0.4 orbital phase coverage (0.56 days). The Goddard High Resolut…
An Investigation into Sulfur Isotopes in the Galactic Cosmic Rays
Thayer, M. R.
Measurements made by the Ulysses High Energy Telescope (HET) have made it possible for the first time to resolve the individual isotopes of sulfur 32S, 33S, and 34S. The measured ratio of Galactic cosmic-ray 34S/32S in the heliosphere is 24.2% +/- 2.7%. Based on this value, the Galactic source…
An Unusual Brightening of the Eclipsing Binary Star AKO 9 in the Globular Cluster 47 Tucanae Observed with the Hubble Space Telescope
Minniti, Dante; Pryor, Carlton; Tinney, Christopher G. +3 more
Fifteen sequential images of the core of the globular cluster 47 Tucanae taken in ultraviolet light with the Hubble Space Telescope have revealed one star that increased in brightness by more than 2 mag in less than an hour. By the end of our observations, this star was the brightest object in the core of the cluster in our bandpass. Aurière et al…
Three-Dimensional Orbits of Metal-poor Halo Stars and the Formation of the Galaxy
Yoshii, Yuzuru; Chiba, Masashi
We present the three-dimensional orbital motions of metal-poor stars in conjunction with their metal abundances, for the purpose of getting insight into the formation process of the Galaxy. Our sample stars, which include metal-deficient red giants and RR Lyrae variables observed by the HIPPARCOS satellite, are least affected by known systematics,…
High-Resolution Hubble Space Telescope Observations of Zn II and CR II Absorption toward the Magellanic Clouds
Roth, Katherine C.; Blades, J. Chris
We present high-resolution (3.5 km s-1) spectra of Zn II and Cr II absorption obtained with the Hubble Space Telescope toward four Magellanic Cloud stars. We have detected absorption from the full extent of the Milky Way disk + halo with an average depletion measure of [Cr/Zn] = -1.07 +/- 0.05. In addition, we identify absorption from t…
Far-Ultraviolet Absorption Lines in the Remnant of SN 1006
Sarazin, Craig L.; Crenshaw, D. Michael; Fesen, Robert A. +3 more
We have obtained a far-ultraviolet spectrum (1150-1600 Å) of a hot subdwarf star behind the remnant of supernova 1006 with the Faint Object Spectrograph (FOS) on the Hubble Space Telescope. The high-quality spectrum is used to test previous identifications of the strong absorption features discovered with the International Ultraviolet Explorer. Th…
The Mass of the Classical Cepheid S Muscae
Carpenter, Kenneth; Robinson, Richard; Beck-Winchatz, Bernhard +2 more
A good determination of the mass-luminosity relation for evolved stars on blue loops can determine the degree of excess mixing in the interiors of their main-sequence companions. In this study we determine the dynamical mass of the Cepheid binary S Muscae. This can be combined with its known luminosity and be fitted on evolutionary tracks to deter…
Extreme Ultraviolet Photometry and Spectroscopy of BL Hydri
Vennes, Stéphane; Szkody, Paula; Howell, Steve B. +2 more
We have analyzed Extreme Ultraviolet Explorer (EUVE) observations of BL Hyi obtained during a high-accretion state in 1995 October. The light curve obtained with the Deep Survey instrument reveals a broad hump covering the phases in which both poles have been known to be active in X-ray emission. In contrast to the X-ray, both poles contribute a c…
The Ultraviolet Extinction Curve for Circumstellar Dust Formed in the Hydrogen-Poor Environment of V348 Sagittarii
Clayton, Geoffrey C.; Drilling, John S.; Hecht, James H. +3 more
New International Ultraviolet Explorer (IUE) spectra with high signal-to-noise ratios have been obtained during the recovery of the hot R Coronae Borealis star, V348 Sgr, from its 1992 minimum. These spectra have been combined with spectra from the IUE archives to obtain a definitive extinction curve for dust recently ejected from this star, and m…
Contemporaneous IUE, EUVE, and High-Energy Observations of 3C 273
Kafatos, M.; Bruhweiler, F. C.; McHardy, I. M. +5 more
We present the results of our 1994 January and 1995 January observations of the quasar 3C 273 obtained with the International Ultraviolet Explorer (IUE) and the Extreme-Ultraviolet Explorer (EUVE). These observations were part of a large multiwavelength campaign to observe 3C 273 from radio through γ-rays. Our 1995 January photometric observations…