Search Publications
VLBI and Optical Astrometry of Southern Extragalactic Radio Sources and Radio Stars
White, Graeme L.; Jauncey, David L.; Lestrade, Jean-Francois +3 more
Mark III very long baseline interferometry (VLBI) has been used to determine the positions of ten compact extragalactic radio sources in the southern hemisphere. These positions are relative to the Jet Propulsion Laboratory VLBI celestial reference frame and are accurate at the 0.01" level, more than an order of magnitude improvement compared to t…
Coordinated Optical and Ultraviolet Observations of DH Leo
Huenemoerder, David P.; Buzasi, Derek L.; Ramsey, Lawrence W. +4 more
Results are reported from contemporaneous KPNO optical spectroscopy, IUE UV spectroscopy, and KPNO R photometry of the DH Leo triple system in spring 1987. The data are presented in tables, graphs, and spectral phase images and discussed in detail. The H-alpha, H-beta, H-gamma, H-delta, and Ca II H and IRT lines are found to have excess emission, …
Rapid Line Variations in the Far-Ultraviolet Spectrum of 21 Com. I. The 1979 Event
Monier, R.
An analysis of archival IUE spectra of 21 Com revealed an instance of large and rapid flux variations on a time scale of 1 hr which occurred on November 15, 1979. Deep and broad features developed in less than 60 min and vanished in about 45 min shortwards of 1720 A. The 1979 event is thought to reflect a transient and abrupt change in the outer l…
A Search for Evidence of Past and Ongoing Mass Loss in the Hot DO Degenerates PG 1159-035, PG 1034+001, and KPD 0005+5106
Sion, Edward M.; Fritz, Matthew L.; Leckenby, Henry J.
The results are reported of a search for evidence of mass loss from three very hot, helium-rich degenerate stars, PG 1034 + 001, PG 1159 - 035, and KPD 0005 + 5106, based upon a search for weak, velocity-displaced line features in high-resolution IUE spectra. The search was entirely negative for PG 1159 - 035 and resulted in the detection of Si IV…
Ultraviolet Fluxes for Globular Clusters in M31: A Rediscussion
Crotts, Arlin P. S.; Cacciari, Carla; Kron, Richard G. +1 more
We discuss long-exposure observations of three bright globular clusters in M31 obtained with both the short- and long-wavelength low-resolution cameras of the International Ultraviolet Explorer satellite. All of the clusters are seen at the longer wavelengths, but only one of the clusters is seen at short wavelengths, and this detection is margina…
The Long Period Binary AL Velorum: The Atmospheric Eclipse of a Bright KO Giant
Shore, Steven N.; Kondo, Yoji; Eaton, Joel A. +1 more
The properties of the AL Vel binary system, a Zeta Aur system containing a B dwarf and a bright K0 giant, are reviewed with reference to IUE observations of its atmospheric eclipse and eclipse of the accretion disk around the B-dwarf component. It is found that the conditions in the chromosphere are rather similar to those in the Zeta Aur supergia…
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…
The Hot DOA1 Degenerate HZ 21: A Search for Circumstellar/Photospheric Metals and Peculiar Absorption at He II
Sion, E. M.; Vauclair, G.; Liebert, J. +2 more
A high-resolution IUE spectrum of the hot DO1 degenerate HZ 21 was obtained by combining US1 + European 2 low-background observing shifts. The SWP image reveals a rich spectrum of interstellar absorption lines with an average velocity in the line of sight to HZ 21 of -30 km/s. However, there is no clear evidence of any highly or lowly ionized meta…
The First UV Spectrum of a Uranian Satellite: IUE Observations of Oberon from 2650-3200 A
Buratti, B. J.; Stern, S. A.; Festou, M. C. +1 more
Using the International Ultraviolet Explorer (IUE) observatory, the first vacuum UV spectrum of Oberon was obtained. The data contain useful information in the spectral range 2650-3200 A. Oberon's UV geometric albedo is found to be flat and essentially featureless with an average value of p(UV) = 0.19 + or - 0.025, and making it possible to extend…