Search Publications
The Initial Mass Function for Early-Type Stars in Starburst Galaxies
Sekiguchi, Kazuhiro; Anderson, Kurt S.
The IMF slope of early-type stars in starburst galaxies is investigated using IUE observations and a technique that utilizes mass-linewidth relations for early-type stars. Fourteen low-resolution IUE spectra of eight starburst galaxies and three H II region galaxies are used to obtain line-strength ratios Si IV (λ1400)/C IV (λ1550). These are comp…
Chromospherically Active Stars. III. HD 26337 = EI Eri: an RS CVn Candidate for the Doppler-Imaging Technique
Fekel, Francis C.; Gillies, Kim; Quigley, Robert +1 more
The variable star HD 26337 = EI Eri is a chromospherically active G5 IV single-lined spectroscopic binary with a period of 1.94722 days. It has moderate strength Ca II H and K emission and strong ultraviolet emission features, while Hα is a weak absorption feature that is variable in strength. The inclination of the system is 46°±12°, and the unse…
Time-Resolved IUE Studies of Cataclysmic Variables. I. Eclipsing Systems of IP Peg, PG 1030 + 590, and V1315 AQL
Szkody, Paula
IUE time-resolved spectra of the high-inclination cataclysmic variables IP Peg, PG 1030+590, and V1315 Aql are analyzed in order to determine the characteristics of the disks, hotspots, and white dwarfs. The UV continuum flux distributions are generally flatter than systems of low inclination and high mass-transfer rate, and the white dwarfs/inner…
Mass to Line Strength Relations from IUE Spectra of Early-Type Stars
Sekiguchi, Kazuhiro; Anderson, Kurt S.
An extensive survey of the 1200 - 1900 Å region in OB type stellar spectra obtained from the IUE archives has been used to establish line-strength versus spectral-type relationships. One hundred and sixty-three low-resolution IUE spectra of 124 well-classified O3 to B5 stars were examined. The authors confirm earlier results that the equivalent wi…
Ultraviolet and Optical Observations of AG Draconis
Lutz, J. H.; Lutz, T. E.; Dull, J. D. +1 more
IUE satellite observations and ground-based spectroscopic observations of the yellow symbiotic star AG Dra obtained at irregular intervals from 1975 to 1984 are presented. No forbidden lnes are observed in the optical, indicating a high density. The hydrogen emission lines often show a second blueshifted component that is not as strong as the main…
A Search for Technetium (Tc II) in Barium Stars
Little-Marenin, Irene R.; Little, Stephen J.
The authors searched without success for the lines of Tc II at 2647.02, 2610.00 and 2543.24 Å in IUE spectra of the barium stars HR 5058, ο Vir, and ζ Cap. The lack of Tc II implies that the observed s-process enhancements were produced more than half a million years ago and supports the suggestion that the spectral peculiarities of barium stars a…
The Moderately Interacting Algol-Type Eclipsing Binary RY Geminorum
Plavec, Mirek J.; Dobias, Jan J.
Ultraviolet spectra of the Algol-type semidetached system RY Geminorum, whose components can be described as A0 V and K0 IV, have been matched to the ultraviolet spectrum by Kurucz (1979) model atmospheres, and a best fit is found for T(eff) = 9150 K. Comparison with standard star spectra requires that this value be raised to 9400 K. The color exc…
On the Absence of Young White Dwarf Companions to Five Technetium Stars
Smith, Verne V.; Lambert, David L.
A search for hot companions to five stars of type MS and S has been carried out using the International Ultraviolet Explorer (IUE) satellite. No hot companions were detected for the MS stars HR 85, 4647, 6702, and 8062, and the S star HR 8714. Limits on the luminosities of possible white dwarf companions provide lower limits of 2 - 5×108
A Nonspherically Symmetric Model for the Peculiar A Star Alpha 2 CVn
Bohm-Vitense, Erika; van Dyk, Schuyler D.
Observations show that in the optical region the peculiar A star α2CVn has a flatter energy distribution during maximum light than during minimum light. This indicates that during maximum light we see a lower-temperature region, but necessarily larger surface area, than during minimum light. This suggests a nonspherically symmetric star…
The Moderately Interacting Algol Binary RS Cephei
Plavec, Mirek J.; Dobias, Jan J.
In agreement with previous observers, it is found that the eclipsing binary RS Cep is an Algol-type semidetached system. From IUE spectra and Lick Observatory optical scans, the spectral types of the components are determined as B9.7e V + G8 III-IV. The effective temperature of the primary star is found to be 9670 K (with an uncertainty of about 1…