Search Publications
IUE observations of proto-planetary and variable planetary nebulae. II. A search for variability in IC 4997 and NGC 6905.
Feibelman, W. A.
A search for ultraviolet variability was conducted for the planetary nebulae IC 4997 and NGC 6905 which have histories of variability in the visible region. Emission line fluxes, line ratios, line profiles, and central stars' temperatures are presented for both objects, as well as stratification effects for several ions in NGC 6905.
The MG II resonance lime emission at 2800 angstrom in stars with different rotational velocities and different metal abundances.
Boehm-Vitense, E.
In many investigations, a study of the Mg II 2800 A emission was conducted in order to derive more information about the correlation of chromospheric emission with the properties of the convection zone. It has been suggested by Ayres and Linsky (1980) that there is a positive correlation between rotation and chromospheric emission at least for bin…
Ultraviolet and X-ray observations of the BL Lac PKS 0548-322.
Kondo, Y.; Mushotzky, R. F.; Urry, C. M. +2 more
Spectrophotometric observations of the BL Lac object PKS 0548-322 were made with ultraviolet and X-ray instruments on the IUE and HEAO-2 satellites. Two observations in each spectral region, one set of which was obtained simultaneously are presented. A power law of energy index approximately 1.0 gives a good description of the data from ultraviole…
The UV continuum spectrum of M81
Torres-Peimbert, S.; Peimbert, M.; Bruzual A., G.
From IUE data the absolute continuum spectrum for the nucleus of M81 in the 1200-3200 A range is presented. The spectrum can be fitted by an old stellar population with a small contribution from horizontal-branch stars. It is found that the number of stars with m less than 0.3 solar mass is negligible. An upper limit for the nonthermal contributio…
Evidence for mass loss at polar latitudes in the Be stars Omega Orionis and 66 Oph
Peters, G. J.
IUE observations of the pole-on Be stars Omega Ori and 66 Oph have revealed the unexpected presence of high velocity (-250 to -850 km/sec), relatively narrow (about 1 A) absorption components to the resonance lines of C IV, Si IV, and Si III. The C IV features show structure indicative of multiple shells or clouds. If Omega Ori and 66 Oph are inde…
Optical and ultraviolet observations of the X-ray globular cluster BO 158 in M31
Cacciari, C.; Bianchi, L.; Fusi Pecci, F. +2 more
It is pointed out that the study of the globular cluster system in a galaxy is very important for understanding the formation, dynamics, and chemical evolution of that galaxy. The present investigation represents an attempt to determine the population content of the globular cluster Bo 158 in M31 through the analysis of its energy distribution in …
The detection of ultraviolet photospheric absorption in the spectra of two Wolf-rayet stars.
Fitzpatrick, E. L.
Narrow, unshifted UV absorption lines, principally of Fe v, have been detected in the spectra of two Wolf-Rayet stars, HD 93162 (WN7) and HD 193793 (WC7). Both stars are known to show upper Balmer-line absorption but exhibit no periodic Doppler shifts that might indicate the presence of a companion. If intrinsic to the Wolf-Rayet stars, these line…
A spectrophotometric analysis of the hot helium-rich white dwarf HD 149499 B.
Sion, E. M.; Wesemael, F.; Guinan, E. F.
A comprehensive analysis of the hot helium-rich white dwarf HD 149499 B is presented based on International Ultraviolet Explorer ultraviolet spectra along with available optical spectra and photometry. Line strengths, line profiles, and continuum fluxes are analyzed in terms of a new grid of hot, high-gravity stellar atmospheres of mixed compositi…
International ultraviolet explorer observations of alf Sco.
Bernat, A. P.
IUE observations of the absorption spectrum of Alpha-2 Sco B2.5 V are presented. These lines arise from matter being lost by the red supergiant primary, Alpha-1 Sco M1.5 Iab, which is passing in front of the B star. There is a factor of 30 spread in the hydrogen column densities derived from different elements on the assumption of solar abundance …
International Ultraviolet Explorer observations of the R AQR jet.
Kafatos, M.; Michalitsianos, A. G.
Ultraviolet spectra were obtained with the International Ultraviolet Explorer of the newly discovered optical-radio jet feature in the symbiotic variable R Aquarii. The far-UV continuum of the jet is characterized by strong continuum which rises with decreasing wavelength in the 1200-2000 A wavelength range and is considerably different in appeara…