Search Publications
The Hot White Dwarf Companions of HR 1608, HR 8210, and HD 15638
Bergeron, P.; Simon, Theodore; Landsman, Wayne
We have obtained low-dispersion IUE spectra of the late-type stars HD 15638 (F3 V), HR 1608 (=63 Eri, K0 IV), and HR 8210 (A8m). Each of these stars had been detected as a strong EUV source with the Wide Field Camera (WFC) aboard the ROSAT satellite. The short-wavelength IUE spectrum of each star reveals the presence of a hot white dwarf companion…
Bernstein waves in the Io plasma torus: A novel kind of electron temperature sensor
Moncuquet, Michel; Meyer-Vernet, Nicole; Hoang, Sang
During Ulysses passage through the Io plasma torus, along a basically north-to-south trajectory crossing the magnetic equator at R~7.8 RJ from Jupiter, the Unified Radio and Plasma Wave experiment observed weakly banded emissions with well-defined minima at gyroharmonics. These noise bands are interpreted as stable electrostatic fluctua…
Interstellar MG II and C IV Absorption toward Markarian 205 by NGC 4319: an ``Optically Thick'' QSO Absorption System
Bowen, David V.; Blades, J. C.
We have used the Goddard High-Resolution Spectrograph aboard HST to detect interstellar Mg II and C IV absorption lines toward Mrk 205, a QSO whose sightline passes within 3 h^-1^ kpc of the foreground galaxy NGC 4319. Absorption is detected from both local Milky Way gas and from NGC 4319, making this the first observation of an isolated, low-reds…
Ultraviolet Line Diagnostics of Accretion Disk Winds in Cataclysmic Variables
Shlosman, Isaac; Vitello, Peter
The IUE data base is used to analyze the UV line shapes of the cataclysmic variables RW Sex, RW Tri, and V Sge. Observed lines are compared to synthetic line profiles computed using a model of rotating biconical winds from accretion disks. The wind model calculates the wind ionization structure self-consistently including photoionization from the …
Discrete wave packets at the proton cyclotron frequency at comet P/Halley
Neubauer, F. M.; Mazelle, C.
We present in this letter the first experimental evidence for wave packets near the local proton cyclotron frequency in the plasma environment of a comet. The observations have been made by the GIOTTO magnetometer experiment (MAG) around comet P/Halley on both sides of closest approach. The waves are always left-handed in the spacecraft frame, ell…
On the nature of the blue light in central cluster galaxies.
Fabian, A. C.; Crawford, C. S.
An excess blue component of light, extended over the innermost few kpc, is observed in several central cluster galaxies. Using a combination of blue optical spectra and IUE data, we show that the spectrum of the excess blue light is consistent with both star formation dominated by the light of B5 stars, and power-law spectra with slopes between λ^…
Saturn's Upper Atmospheric Hazes Observed by the Hubble Space Telescope
Karkoschka, Erich; Tomasko, Martin G.
We observed Saturn with the Hubble Space Telescope at wavelengths 0.30-0.89 µm for the purpose of determining the distribution of hazes. In the stratosphere, haze optical depths in the ultraviolet are essentially zero for midnorthern latitudes, are small (∼0.2) at low latitudes and mid-southern latitudes, but large (almost unity) above 70° n…
Correlated variations of UV and radio emissions during an outstanding Jovian auroral event
Moos, H. W.; Bame, S. J.; Zarka, P. +6 more
An exceptional Jovian aurora was detected in the FUV on December 21, 1990, by means of Vilspa and Goddard Space Flight Center (GFSC) International Ultraviolet Explorer (IUE) observations. This event included intensification by a factor of three between December 20 and 21, leading to the brightest aurora identified in the IUE data analyzed, and, in…
PG 0308+096 and PG 1026+002: Two New Short Period Binary Stars Resulting From Common-Envelope Evolution
Green, Richard F.; Sion, Edward M.; Saffer, Rex A. +5 more
Ultraviolet spectroscopy, optical spectroscopy, and spectrophotometry have been used to study the excess UV stars PG 0308 + 096 and PG 1026 + 002. Both objects are short-period binary systems, each containing a DA white dwarf star and a dM star. Orbital periods of approximately 0.284 day for PG 0308 + 096, and aproximately 0.597 day for PG 1026, h…
Spectral analysis of DY Centauri, a hot R Coronae Borealis star with an unusually high hydrogen content.
Heber, U.; Jeffery, C. S.
The photospheric parameters of DY Cen, an H-deficient early-B supergiant that is spectroscopically similar to the pulsating, extreme-He star BD-9 deg 4395, have been derived from high-resolution spectra via atomic data and line-blanketed model atmospheres. DY Cen is shown to be a metal-poor EHe star whose composition supports an anticorrelation be…