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Ultraviolet spectroscopy of the recurrent nova U SCO during outburst.
Gallagher, J. S.; Williams, R. E.; Truran, J. W. +3 more
Observations of the recurrent nova U Sco during the 1979 outburst are presented, and the spectral evolution is found to differ from that of other recurrent novas. Spectra are dominated by emission lines, and the strong forbidden-line emission characteristic is conspicuously absent. A method to determine masses of nova shells is outlined, and an an…
A change in light curve asymmetry and the ephemeris of CYG X-3.
van der Klis, M.; Bonnet-Bidaud, J. M.
Cygnus X-3 was observed in the 2-12 keV range for 40 days in May-June 1980. The mean 4.8 h light curve was seen to change significantly in a way suggestive of the existence of an underlying binary with an eclipse duration of 40 percent of the period. The observed time of X-ray minimum was found to increase the level of confidence of a period deriv…
H2 emission in the EUV spectrum of T Tauri and Burnham's nebula
Jordan, C.; Wilson, R.; Brown, A. +2 more
Emission in the Lyman bands of H2 has been detected in an extreme ultraviolet (EUV) spectrum of T Tauri and its adjacent nebula, obtained with the international UV explorer (IUE) satellite. We report here that the emission is in a progression which can be excited through fluorescence with the red wing of the H Lyα line, as found also in…
Ultraviolet interstellar extinction toward 1367 stars observed by ans.
Savage, B. D.; Meyer, D. M.
Five-band UV photometry is used to investigate the character of interstellar extinction toward 1367 stars of spectral type B3 and earlier, with observations producing a galactic average of 5.11, 4.78, 6.52, 4.10 and 1.95 at 1550, 1800, 2200, 2500, and 3300 A, respectively. Differences in the strengths of the UV extinction features of these stars a…
IUE and ground-based spectroscopic observations of the S Dor-type LMCvariable R 71 during minimum state.
Stahl, O.; Wolf, B.; Appenzeller, I.
Using the IUE satellite, high resolution UV spectrograms are obtained of the S Dor type variable R 71 in the LMC. The IUE observations are supplemented by coordinated ground-based high dispersion spectroscopy and photometric observations. For the expanding envelope, a surprisingly low temperature of only about 6000 K and an apparently decelerated …
Detailed empirical models for the winds of early-type stars.
Olson, G. L.; Castor, J. I.
Owing to the recent accumulation of ultraviolet data from the IUE satellite, or X-ray data from the Einstein (HEAO 2) satellite, of visible data from ground based electronic detectors, and of radio data from the Very Large Array (VLA) telescope, it is becoming possible to build much more complete models for the winds of early-type stars. The prese…
IUE observations of eight dwarf novae : a study of the outburst cyclefrom 0.12 to 3.5 microns.
Szkody, P.
The dwarf novae are a class of close binary systems with a G-M star transferring mass to a white dwarf. The transferred material accumulates in a disk and accretes onto the white dwarf. Dwarf novae are characterized by outbursts on time scales of weeks to months possibly triggered by instabilities in the disk. To test the steady state models and t…
The 1979 outburst of U Scorpii.
Willis, A. J.; Barlow, M. J.; Watson, M. G. +8 more
Optical and ultraviolet observations are presented of the 1979 outburst of the recurrent nova U Sco. For the first time the evolution through outburst is documented photometrically and spectroscopically. Lines of the following ions are identified: H I, He II, C IV, N III, N IV, N V, O IV, O VI and Si IV. No forbidden lines were observed. Mg I was …
Anomalous extinction in the planetary nebula Abell 30.
Greenstein, J. L.
The stellar continuous energy distribution from 8000 to 1250 A in Abell 30 is quite peculiar. The observed flux can be understood if a hot central star (approximately 200,000 K) is immersed in an absorbing dust cloud which has anomalous absorption with its peak near 2470 A. The dust nebula is a strong infrared source, maintained by conversion of t…
Ionized species observed in the spectrum of the nearby white dwarf G 191-B2B.
Kondo, Y.; Bruhweiler, F. C.
High-resolution spectra of the nearby (48 pc) white dwarf G191-B2B, obtained with the International Ultraviolet Explorer, reveal sharp resonance lines of N V, C IV, and Si IV. The origin of these features is most likely linked to the white dwarf, possibly being formed in an expanding halo around the star. Interstellar lines of C II, N I, Mg II, Si…