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The apsidal motion of the eccentric eclipsing binary DI Herculis - an apparent discrepancy with general relativity.
Guinan, E. F.; Maloney, F. P.
DI Her is an important system for studying relativistic apsidal motion because of the large masses and small fractional radii of its components, the large orbital eccentricity and its relatively short period, and the favorable orientation of its orbital plane to our line of sight producing deep eclipses. In addition, the long history of eclipse ti…
Multiwavelength observations of eleven cataclysmic variables.
Szkody, P.
Observations covering nonsimultaneous IUE and optical spectroscopy and broadband optical and infrared photometry of ten dwarf novae (TY Psc, UV Per, TW Vir, V503 Cyg, AF Cam, CM Del, AR And, VW Vul, FO Aql, and CY Lyr) and one novalike system (V425 Cas) at various outburst states are presented. The author uses the multiwavelength coverage to probe…
The magnetically controled stellar wind of HD 21699.
Sonneborn, G.; Shore, S. N.; Brown, D. N.
The authors report the discovery of a magnetically controlled stellar mass outflow in the helium-weak sn star HD 21699 = HR 1063. IUE observations show that the C IV resonance doublet is variable on the rotational time scale of about 2.5 days, and that there are no other observable spectrum variations in the UV. The magnetic field reverses sign on…
The structure of Herbig-Haro object 43 and Orion dark cloud extinction.
Cohen, M.; Dopita, M. A.; Schwartz, R. D.
New ultraviolet and optical observations of Herbig-Haro object No. 43 are reported. Continuum and emission-line fluxes in the wavelength range 1250 to 7350 A have been measured. The continuum fluxes are best matched by an enhanced H exp 0 two-photon component added to H free-bound emission, assuming a Theta Ori extinction curve with E(B - V) = 0.2…
HD 160538 and HD 185510 : two active-chromosphere stars with hot companions.
Fekel, F. X.; Simon, T.
Short-wavelength ultraviolet spectra of two active-chromosphere giants, HD 160538 and HD 185510, show hot stellar continua and Lα absorption features. The hot companion of HD 160538 is a white dwarf whose ultraviolet spectrum is matched best to the energy distribution of a Teff = 30000K and log g = 8 model atmosphere. The ultraviolet sp…
Extreme Be stars in the Magellanic Clouds.
Humphreys, R. M.; Garmany, C. D.
In the course of a spectroscopic investigation of the O-type stars in the Magellanic Clouds, a population of luminous Be stars was serendipitously encountered. They are here referred to as extreme Be stars, following the terminology used by Schild (1966) for a population of Be stars in the region of h and Chi Persei which lie significantly above t…
A redetermination of the luminosity, distance, and reddening of beta Lyrae.
Plavec, M. J.; Dobias, J. J.
The authors have redetermined the distance to β Lyrae and found that it probably lies between 345 and 400 pc, with the most likely value being 370 pc. With the corresponding true distance modulus of 7.8 mag, they find that the eclipsing system of β Lyrae has a maximum absolute visual magnitude of -4.7 mag. Using Wilson's model, the authors conclud…
UV and optical spectroscopy of OB stars in M 31 and M 33.
Bianchi, L.; Hutchings, J. B.; Massey, P.
IUE UV spectra and MMT blue spectra have been obtained for 'normal' OB supergiant stars in M31 and M33. The authors classify the stars as late O to early B. UV and visible fluxes yield consistent values for the effective temperature, bolometric magnitudes, and extinction for the stars. The UV resonance lines have very low outflow velocities compar…
X-ray luminosity and the hydrogen-line ratios of quasars and Seyfert galaxies.
Kriss, G. A.
New observations of the Ly-alpha/H-alpha ratio in a set of X-ray-selected active galactic nuclei and an archival study of International Ultraviolet Explorer (IUE) observations of Ly-alpha in low-redshift quasars and Seyfert galaxies have been used to form a large sample (49 objects) for studying the influence of soft X-rays on the enhancement of B…
He 2-36 : a planetary nebula with a high-velocity jet ?
Feibelman, W. A.
The ultraviolet spectrum of the planetary nebula He2-36 was observed in the low-dispersion mode of the IUE. Strong emission lines of C III], He II, and C IV are observed, as well as some weak lines and a moderately strong stellar continuum, suggesting a hot companion to the visual A2 III central star. The extinction to He2-36 was determined from t…