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Extragalactic H II regions in the UV : implications for primeval galaxies.
Terlevich, R.; Meier, D. L.
Three extragalactic regions of rapid star formation with redshifts great enough to separate the Lyman-alpha region from geocoronal Lyman-alpha have been observed with the IUE satellite. Only the low metal abundance object had detectable Lyman-alpha emission with Lyman-alpha/H-alpha of about 6; the other two have Lyman-alpha/H-alpha less than 0.6 (…
Outer atmospheres of cool stars. VIII. IUE observations and chromospheric models for the supergiant stars beta Draconis, epsilon Geminorum and alpha Orionis.
Eriksson, K.; Linsky, J. L.; Basri, G. S.
A semiempirical modeling of stellar chromospheres is extended to late-type supergiants, where computations match high-resolution, absolute-flux profiles of the Ca II K and Mg II h and k lines. IUE UV spectra of Epsilon Gem and Alpha Ori show no evidence of emission lines formed at temperatures greater than 10,000 K, leading to the computation of c…
Search for gamma-radiation from extragalactic objects using a likelihood method.
Bignami, G. F.; Hermsen, W.; Masnou, J. L. +5 more
A search through COS-B data for gamma-radiation from a number of extragalactic objects reveals no strong evidence for any positive identification except, as already reported, for the region around the quasar 3C273. Upper limits to the photon fluxes from active extragalactic objects are evaluated using a likelihood method. They reinforce the conclu…
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…