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The unexpected ultraviolet variability of Herbig-Haro object 1.
Shull, J. M.; Brugel, E. W.; Bohm-Vitense, E. +1 more
The line fluxes of the C IV 1550 A and semiforbidden C III 1909 A emission lines in HH 1 are noted to have monotonically decreased by factors of 4-6 between 1979 and 1983, despite a lack of indications of optical range changes. The thickness of the shocked layers and preshock density can be estimated on the basis of these rapid changes, with resul…
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…
An analysis of scattered light in low dispersion IUE spectra.
Clarke, J. T.; Basri, G.; Haisch, B. M.
A detailed numerical simulation of light scattering from the low-resolution grating in the short wavelength spectrograph of the IUE Observatory was developed, in order to quantitatively analyze the effects of scattering on both continuum and line emission spectra. It is found that: (1) the redistribution of light by grating scattering did not appr…
The newly discovered eclipsing supergiant 22 Vulpeculae.
Kondo, Y.; Ake, T. B.; Parsons, S. B.
Spectra obtained with the IUE satellite have led to the discovery of a new atmospheric eclipsing binary belonging to the ζ Aurigae class of stars, 22 Vul. This system is unique in that it is the first one found with a G-type primary (G3 Ib-II), while the spectral type of the secondary is the latest (B9) and its period is the shortest (249 days) of…
IUE spectra of GO V-G5 V solar-type stars.
Basri, G.; Haisch, B. M.
An atlas of IUE short-wavelength spectra for a set of 14 bright G0 V-G5 V stars are presented, and it is shown that these manifest a range of qualitatively different chromospheric and transition region spectra and significant differences in radiative flux originating at the temperature minimum level. A comprehensive survey of observational data an…
The distribution of the local interstellar medium derived from MG II column densities towards seven cool stars.
Molaro, P.; Franco, M. L.; Beckman, J. E. +2 more
High resolution spectra containing the Mg II h and k resonance doublet have been obtained using the long wavelength spectrometer of IUE, for 7 late-type stars (F0 to G8). In one of these stars, β Hyi, two sharp absorption features were detected against the chromospheric emission cores. Using the study of Crutcher (1982) the authors can employ the …
IUE observations of RCB stars during extinction minima.
Evans, A.; Whittet, D. C. B.; Bode, M. F. +2 more
The R Coronae Borealis stars RY Sgr and MV Sgr have been observed with the long-wavelength (LWR) camera on the IUE satellite during deep extinction minima. The ultraviolet spectrum of RY Sgr showed a rich chromospheric spectrum, similar to that observed in the optical spectrum of this object during previous extinction episodes. Near-simultaneous o…
Gas and star content and spatial distribution in the giant extragalactic H II region TOL 89.
Boksenberg, A.; Durret, F.; Bergeron, J.
Tol 89 is a giant H II region 2.5 kpc in diameter, located in one of the arms of the spiral galaxy NGC 5398. We have observed this object in the Uv with the International Ultraviolet Explorer, and at optical wavelengths with long slit spectrophotometric equipment. The UV spectrum of Tol 89 reveals P Cygni profiles, characteristic of stars with str…
High-dispersion ultraviolet spectra of the peculiar star RX Puppis.
Kafatos, M.; Michalitsianos, A. G.; Fahey, R. P.
High spectral resolution observations of the peculiar star RX Puppis obtained with the International Ultraviolet Explorer suggest the presence of a complex gaseous ring system which surrounds an accreting hot secondary. The anomalous line intensity ratio of the C IV 1548, 1550 A doublet during the observations exceeded the optically thick limit, i…
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…