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Stellar Mass Loss in Late B-Type Supergiants
Dufton, P. L.; Bates, B.; Gilheany, S. +1 more
A study using archive IUE data of time-varying mass loss has been carried out for a sample of 12 supergiants in the spectral range B5–B9. Additionally dedicated IUE velocity-time observations of 'discrete absorption components' (DAC) in the UV resonance lines have been made for one of the stars (βOri), while optical data obtained for this star sho…
Chromospheric Variability of M Giant Semiregular Variables
Johnson, Hollis R.; Eaton, Joel A.; Cadmus, Robert R., Jr.
The results of monitoring the chromospheric emission from three M giant semiregular variables, W Cyg, NU Pav, and Theta Aps at low dispersion with the IUE satellite are reported along with high-dispersion IUE spectra for R Lyr and Delta(2) Lyr. The chromospheric emission is variable in all of the first three stars, and the Mg II strength generally…
Model Atmosphere Analysis of the DZ White Dwarf K789-37
Koester, D.; Kilkenny, D.; Wegner, G.
This paper presents new observations and an analysis using model atmosphere techniques of the recently discovered DZA white dwarf K789 - 37. The effective temperature derived is 9500 + or - 500 K. Abundances are determined for the elements hydrogen, magnesium, calcium, and iron, as well as upper limits for carbon and silicon. The abundances are ve…
Ephemerides of the 48 HIPPARCOS minor planets for the year 1991
Bec-Borsenberger, A.
To be observed by Hipparcos, the position of each object has to be known with an accuracy of 1 arcsecond and its magnitude with an accuracy of 0.5 mag. Therefore, the orbital elements of 48 selected minor planets of the Hipparcos mission, have been improved in order to extrapolate their ephemerides with the accuracy required. These ephemerides for…
The Changing Soft X-Ray Lightcurve of the Am-Herculis System Mr-Serpentis = PG:1550+191
Stella, L.; Osborne, J. P.; Angelini, L.
We report the first soft X-ray light curves of the AM Her system MR Ser, all obtained within a 4-month interval in 1984. The source was serendipitously detected on three occasions by the EXOSA T low-energy telescope, and one observation was made in which MR Ser was the target. MR Ser was probably in a high optical state throughout, although it was…
FG Sagittae: No Hot Companion?
Feibelman, Walter A.; Bruhweiler, Frederick C.
The nucleus of the planetary nebula He 1-5 (= PK 60 -7 deg 1), the variable star FG Sge, was observed with the SWP camera of the International Ultraviolet Explorer satellite to detect a hot companion of the star, if such a companion exists. The observation found no evidence for the existance of a hot companion in the 1200-2000 A range of the SWP c…
Terminal Velocities of the Winds from Rapidly Rotating OB Stars
Friend, David B.
This paper presents measurements of terminal velocities of OB stars which are rapid rotators, based on archival high-dispersion IUE spectra of the C IV resonance doublet. The terminal velocities of the most rapidly rotating stars appear to be systematically lower than those of the less rapidly rotating stars (at least for the cooler stars), althou…
The ultraviolet spectrum of solar analogs.
Altamore, A.; Rossi, C.; Rossi, L. +1 more
The ultraviolet high resolution IUE spectrum between 2600 and 3200 A of a sample of stars classified as solar analogs by Hardorp (1982 and references therein), including the southern solar twin HR 2290, is studied. A list of Fe II absorption line identifications and equivalent widths in the considered spectral region is presented. An analysis of t…
The long-period binary UU CANCRI as a system that has reversed its mass ratio.
Eaton, J. A.
UU Cnc is a 96-d binary system (K4 111+?) which has been interpreted as a contact binary, presumably representing the common-envelope stage of evolution. Since this is such a bizarre possibility, we have tested it by using the rotational velocity to determine the mass ratio and by obtaining lUE observations to search for the hot, accreting source …
The photospheric temperature and metal abundance of the compact star H 1504+65.
Barstow, M. A.; Tweedy, R. W.
A new analysis of an Exosat low-energy telescope observation of the hot compact star H1504 + 65 is presented. Earlier results had failed to take into account the large point-spread function produced by the boron filter, and hence the count rate had been underestimated by a large factor. On comparing the data with a new grid of model atmospheres co…