Search Publications
A Hubble Space Telescope Survey for Resolved Companions of Planetary Nebula Nuclei
Bond, Howard E.; Ciardullo, Robin; Fullton, Laura K. +3 more
We report the results of a Hubble Space Telescope ``snapshot'' survey aimed at finding resolved binary companions of the central stars of Galactic planetary nebulae (PNe). Using the the Wide Field and Planetary Camera and Wide Field Planetary Camera 2, we searched the fields of 113 PNe for stars whose close proximity to the central star suggests a…
The Metagalactic Ionizing Radiation Field at Low Redshift
Shull, J. Michael; Giroux, Mark L.; Penton, Steven V. +2 more
We compute the ionizing radiation field at low redshift, arising from Seyferts, QSOs, and starburst galaxies. This calculation combines recent Seyfert luminosity functions, extrapolated ultraviolet fluxes from our IUE-AGN database, and a new intergalactic opacity model based on Hubble Space Telescope and Keck Lyα absorber surveys. At z=0 for AGNs …
The Deuterium Abundance at z=0.701Z = 0.701 toward QSO 1718+4807
Savage, Blair D.; Lu, Limin; Burles, Scott +3 more
We present constraints on the deuterium-to-hydrogen ratio (D/H) in the metal-poor gas cloud at redshift z=0.701 toward QSO 1718+4807. We use new Keck spectra in addition to Hubble Space Telescope (HST) and International Ultraviolet Explorer spectra. We use an improved redshift and a lower H I column density to model the absorption. The HST spectru…
The Effective Temperature of Arcturus
Lynas-Gray, A. E.; Griffin, R. E. M.
We construct an empirical energy distribution for Arcturus from published scans, integrate it to obtain the total flux, and combine the latter with precise interferometric measurements of the limb-darkened angular diameter to derive the effective temperature. We conclude that the best value that can be derived within the framework of the associate…
Ultraviolet Spectral Classification of O and B Stars in the Large Magellanic Cloud
Bruhweiler, Frederick C.; Smith Neubig, Margaret M.
In this extension of our previous ultraviolet classification study of Small Magellanic Cloud stars, we construct an ultraviolet classification system for stars of the Large Magellanic Cloud, a galaxy with a metallicity intermediate to those of the Milky Way and the SMC. Employing the same method as was used for the SMC, we compile a set of LMC spe…
The Integrated Spectra of M32 and of 47 Tucanae: A Comparative Study in the Mid-Ultraviolet With IUE
Rose, James A.; Deng, Shibing
Low-resolution mid-UV spectra of M32 and 47 Tuc have been extracted from the IUE archival database, along with spectra of 41 F and G dwarfs with well-determined atmospheric parameters and integrated spectra of 24 Galactic globular clusters. We have used five mid-UV spectral indices defined by Fanelli et al. to constrain the stellar content of M32 …
The Fall and Rise of V854 Centauri: Long-Term Ultraviolet Spectroscopy of a Highly Active R Coronae Borealis Star
Marang, Fred; Clayton, Geoffrey C.; Lawson, Warrick A. +6 more
We examine long-term low-dispersion International Ultraviolet Explorer SWP and LWP spectroscopy of the R Coronae Borealis (RCB) star V854 Cen, obtained across the deep (DeltaV>6 mag) 1991, 1992-1993, and 1994 declines. We also report the optical light curve for the star in the interval 1987-1998, including multicolor photometry obtained during …
The Relationship between Ultraviolet Line Emission and Magnetic Field Strength in Magnetic Cataclysmic Variables
Howell, Steve B.; Cash, Jennifer; Mason, Keith O. +1 more
We present the first UV spectral observations of six magnetic cataclysmic variables discovered by the ROSAT Wide Field Camera (WFC). Using the^ International Ultraviolet Explorer (IUE), 1200-3400 Å spectra were obtained of the AM Herculis stars RE 0531-46, RE 1149+28, RE 1844-74, QS Tel (RE 1938-46), and HU Aqr (RE 2107-05) and the DQ Herculis sta…
A Second Catalog of Orbiting Astronomical Observatory 2 Filter Photometry: Ultraviolet Photometry of 614 Stars
Meade, Marilyn R.
Ultraviolet photometry from the Wisconsin Experiment Package on the Orbiting Astronomical Observatory 2 (OAO 2) is presented for 614 stars. Previously unpublished magnitudes from 12 filter bandpasses with wavelengths ranging from 1330 to 4250 Å have been placed on the white dwarf model atmosphere absolute flux scale. The fluxes were converted to m…
Voyager Far-Ultraviolet Observations of Globular Clusters
Chavez, M.; Landsman, Wayne B.; Holberg, Jay B.
We report on the observations of nine globular clusters carried out by the Voyager ultraviolet spectrometers (UVSs). Three of the observed clusters, M13, NGC 6752, and M70, exhibit an intense far-ultraviolet (FUV) spectrum down to the Lyman limit. However, the spectrum obtained for NGC 6752 is heavily contaminated by the nearby star HD 177999 for …