Search Publications
Search for X-Rays from the Region of the Aries-Perseus Flasher
Lewin, Walter H. G.; van Paradijs, Jan; Damen, Eugene +4 more
The region containing the Perseus flasher (Katz et al., 1986) was observed for 5.4 hr with the EXOSAT observatory. Upper limits (2 σ levels of confidence) to a point source with a steady X-ray flux were 2×10-12erg cm-2s-1 (0.1 - 2 keV) and 6×10-12erg cm-2s-1 (1 - 20 keV). Upper limi…
X-ray and optical observations of the flare star Wolf 630 AB and of VB 8 G.
Tagliaferri, G.; White, N. E.; Doyle, J. G. +1 more
Results from three EXOSAT observations of Wolf 630 AB are reported. Two X-ray flares have been detected, one simultaneous with an Hα flare. During the second observation a large increase in the X-ray flux from the nearby star VB 8 was also detected.
A spectrophotometric study of the Algol binary system RX Geminorum.
Plavec, Mirek J.; Dobias, Jan J.
IUE low-dispersion spectra and optical ITS scans of the semidetached Algol-type binary system RX Gem have been obtained. The spectral type of the primary component was determined to be A0, with good accuracy. Since the primary eclipse is only partial, the spectral type of the cooler component has been determined with less accuracy as K2 (+ or - 2)…
Interstellar absorption lines in the spectra of theta-Crateris and 14Canum Venaticorum.
de Boer, K. S.; Grewing, M.; Bianchi, L. +1 more
High-resolution (≡0.2 Å) ultraviolet spectra of the two B9 stars θ Crateris (HD 100889) and 14 Canum Venaticorum (HD 113797) have been obtained with the IUE satellite. Since both are fast rotators interstellar absorption lines can easily be separated from the stellar features allowing a determination of the Mg I, Mg II, Fe II, Si II, and S II colu…
The peculiar planetary nebula 75+35 1.
Feibelman, Walter A.
The high galactic latitude planetary nebula 75+35°1 was observed in the low-dispersion mode of the IUE. The UV spectrum is characterized by a strong continuum that matches the energy distribution of a blackbody curve of 90,000K±5000K. A color temperature of 94,000K±4000K is derived. The spectral type mimics that of an O7.5 V star. A very strong N …
A photometric and spectroscopic comparison of the cataclysmic variables on the 2 sides of the period gap and at a specific orbital period
Szkody, P.
New and previously existing photometric colors and spectroscopic H and He line strengths are used to compare CV disk systems below the period gap (P=80–130 min) with those directly above (P=190–240 min). Significant differences are found in the mean U-B, V-J colors and in the Hß equivalent widths on the 2 sides of the gap. A detailed comparison fr…
Solar and Stellar Coronae
Pallavicini, R.
Our present understanding of coronal heating, structuring and variability that has emerged from space observations of the Sun and nearby stars are reviewed. It is shown that a basic analogy exists between solar coronal physics and the phenomena observed in the coronae of other late-type stars. Recent X-ray observations of stellar coronae from EXOS…
EXOSAT Medium Energy Observations of CYGNUS-X-2 Spectra and Qpos
Maraschi, L.; Tanzi, E. G.; Chiappetti, L. +3 more
We report on a series of observations of Cyg X-2 obtained with EXOSAT in September 1983 at five phases in a single orbital cycle (P=9.8 days, see Cowleyet al. 1979). Here we present spectral data obtained with the Argon counters of the Medium Energy experiment (ME) (see Turneret al. 1981), together with the search of Quasi Periodic Oscillations (Q…
A rotational-state population analysis of the high-resolution IUE observation of CS emission in comet P/Halley
Jackson, W. M.; Prisant, M. G.
The high resolution spectrum of comet P/Halley has been measured in the region of the CS emission. CS in comet Halley is produced by photodissociation of CS2 and subsequently re-excited by broad band solar radiation. An inversion procedure is introduced to extract the rotational population distribution from the dispersed fluorescence sp…
The may 1985 Super Outburst of Oy-Carinae - Part Two - Phase-Resolved IUE Spectroscopy and EXOSAT Observations
Sonneborn, G.; van Paradijs, J.; Charles, P. A. +4 more
We present ultraviolet and X-ray observations of the eclipsing SU UMa dwarf nova OY Car early in the decline from a superoutburst. From the UV emission line spectrum and lack of X-ray eclipse, we deduce the presence of an extended coronal region.