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Observations of stellar winds in high-mass X-ray binaries : evidence for a non-monotonic velocity structure.
van Loon, J. Th.; Hammerschlag-Hensberge, G.; Kaper, L.
We report variations with orbital phase in UV resonance lines of HD77581 (B0.5 Iab), the optical counterpart of the high-mass X-ray binary system Vela X-1 (4U0900-40), occurring at low and intermediate negative velocities. We argue that these variations are caused by ionization effects in the stellar wind by the X-ray source, just like the well-kn…
The soft X-ray excesses of high-luminosity AGN.
Saxton, R. D.; Turner, M. J. L.; Ohashi, T. +3 more
LE and ME spectra of 12 quasars from the EXOSAT data base have been analysed in a search for soft excesses. We have been able to quantify the soft excesses more accurately by using spectral indices for the ME taken from the much more sensitive Ginga observations of the same quasars. Eight quasars show a significant soft excess and the remaining fo…
In-Flight Performance and Preliminary Results from the Far Ultraviolet Space Telescope (Faust) Flown on ATLAS-1
Bowyer, Stuart; Lampton, Michael; Sasseen, Timothy P. +1 more
In 1992 March the Far Ultraviolet Space Telescope was flown as part of the NASA ATLAS-1 mission. We describe the in-flight instrument performance and provide a preliminary view of some of the results. Twenty-two wide-field far-ultraviolet images were obtained. At this stage of our analysis, we have far-ultraviolet photometry for more than 4800 sou…
IK Peg : a nearby, short-period, Sirius-like system.
Stickland, D. J.; Kellett, B. J.; Wonnacott, D.
The system IK Peg has been known to be a binary for over 60 years but the secondary has never been identified. The detection of this system in the British Wide Field Camera All-Sky Survey in the EUV has enabled the secondary to be positively identified as a white dwarf. Fits to EUV survey data, the first IUE spectrum, and archival X-ray data indic…
Far-Ultraviolet Radiation from Disk Globular Clusters
Minniti, Dante; Rich, R. M.; Liebert, James
IUE spectra obtained in a survey of the metal-rich disk system of globular clusters are presented. Significant FUV fluxes were detected in the 1200-2000-A short-wavelength (SWP) range of the IUE Observatory in several disk globular clusters. These clusters are the most metal-rich known to have an FUV flux. Three clusters show spectral energy distr…
Ulysses plasma electron observations in the Jovian magnetosphere
McComas, D. J.; Forsyth, R. J.; Bame, S. J. +4 more
The electron analyzer of the solar wind plasma experiment aboard the Ulysses spacecraft measured the plasma properties of the Jovian magnetosphere and surrounding regions during the February 1992 encounter with Jupiter. In addition to sampling a new region of the Jovian magnetosphere, the Ulysses electron measurements were unique in that they incl…
Optical polarization of 1000 stars within 50 PC from the Sun
Leroy, J. L.
We have prepared a catalogue of optical polarization measurements for 1000 stars closer than 50 parsecs from the Sun. The distances, which are presently those given in the Sky Catalogue 2000.0, 2nd edition (Hirshfeld et al. 1991) are provisional: they will be replaced later by the much safer parallaxes which will result from the Hipparcos mission.…
A Spectroscopic and Photometric Study of FK Comae in 1989
Huenemoerder, David P.; Buzasi, Derek L.; Ramsey, Lawrence W. +1 more
Results of an observational campaign, coordinated between visual photometry, optical spectroscopy, and UV spectroscopy, to elucidate the characteristics of FK Comae are presented. The photometry showed complicated but systematic behavior. Photospheric absorption lines were distorted by a Doppler-shifted bump caused by dark starspots resulting in s…
Identification of ``small'' dust impacts in the Ulysses dust detector data
Grün, E.; Linkert, D.; Linkert, G. +2 more
Since October 1990, 3 weeks after the launch of the Ulysses spacecraft, the dust detector onboard recorded impacts of cosmic dust particles. Besides dust impacts, the detector recorded noise from a variety of sources. So far, a very rigid scheme had been applied to eliminate noise from impact data. The data labeled "big" dust impacts previously le…
Source characteristics of Jovian narrow-band kilometric radio emissions
Kaiser, M. L.; Desch, M. D.; Zarka, P. +5 more
New observations of Jovian narrow-bank kilometric (nKOM) radio emissions were made by the Unified Radio and Plasma Wave (URAP) experiment on the Ulysses spacecraft during the Ulysses-Jupiter encounter in early February 1992. These observations have demonstrated the unique capability of the URAP instrument for determining both the direction and pol…