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Masses and Densities of Pluto and Charion
Null, G. W.; Owen, W. M.; Synnott, S. P.
We have analyzed HST Wide Field Camera CCD images of Pluto, Charon, and a background star to observe Pluto's barycentric motion and to determine the individual masses and bulk densities of Pluto and Charon. The most fundamental new result was an accurate solution for a previously undetermined parameter, the Charon/Pluto mass ratio q; the new solut…
IUE Temperatures for White Dwarf Stars in and Around the ZZ Ceti Instability Strip
Kepler, S. O.; Nelan, E. P.
We have analyzed all the archival IUE images of the DA4 and DA5 white dwarfs with model atmosphere fluxes incorporating the quasi-molecular opacities to obtain a consistent set of temperatures for both the variables and nonvariables in and around the ZZ Ceti instability strip. We have found four nonvariable stars inside the instability strip. Take…
NGC 4313. II. Hubble Space Telescope I-Band Surface Photometry of the Nuclear Region
Benedict, G. F.; Franz, O. G.; Hemenway, P. D. +11 more
We present a Hubble Space Telescope I-band Planetary Camera image of the nuclear region of NGC 4314. This is an anemic barred galaxy with recent star formation confined to a nuclear ring. These data resolve the nuclear ring into multiple sites of new star formation and resolve associated dust lanes into discrete clouds. Unsharp masking of a Lucy-R…
Imaging of the Gravitational Lens System PG 1115+080 With the Hubble Space Telescope
Holtzman, J. A.; Ewald, S. P.; Schneider, D. P. +14 more
This paper is the first of a series presenting observations of gravitational lenses and lens candidates, taken with the Wide Field/Planetary Camera (WFPC) of the Hubble Space Telescope (HST). We have resolved the gravitational lens system PG 1115+080 into four point sources and a red, extended object that is presumably the lens galaxy; we present …
RE 1016-053: A Pre-Cataclysmic Binary, and the First Extreme Ultraviolet and X-Ray Detections of DAO White Dwarf
Barstow, M. A.; Bergeron, P.; Holberg, J. B. +4 more
Photometric observations and analysis of the optical, UV, EUV, and X-ray spectra are presented for the EUV/X-ray source RE 1016-53. Multiwavelength observations of RE 1016-53 point out that it is a precataclysmic binary. Optical spectra exhibit the steep blue continuum and Balmer absorption typical of a hot white dwarf, but there are bright, narro…
Chromospherically active Stars. XI. Giants With Compact Hot Companions and the Barium Star Scenario
Henry, Gregory W.; Fekel, Francis C.; Busby, Michael R. +1 more
We have determined spectroscopic orbits for three chromsopherically active giants that have hot compact companions. They are HD 160538 (KO III + wd, P = 904 days), HD 165141 (G8 III + wd, P approximately 5200 days), and HD 185510 (KO III + sdB, P = 20.6619 days). By fitting an IUE spectrum with theoretical models, we find the white dwarf companion…
The Violent Interstellar Environment Around the Wolf-Rayet Star HD 192163
Nichols-Bohlin, Joy; Fesen, Robert A.
IRAS Skyflux IR images, high-dispersion IUE UV spectra, optical spectra, and optical interference filter images are used to investigate the nature of the interstellar environment around the Wolf-Rayet star HD 192163. IRAS images show an apparent 1.5 x 1.8 deg IR emission shell very nearly centered on HD 192163, which is designated G75.5+2.4. It is…
Hydrogen and Metal Absorption Lines in PKS 0405-123 From the Halos of Low Redshift Galaxies
Filippenko, Alexei V.; Bechtold, Jill; Blades, J. C. +6 more
Hubble Space Telescope ultraviolet spectra and ground-based optical spectra of the bright quasar PKS 0405 - 123 are used to identify two absorption-line systems probably produced by the halos of foreground galaxies. The quasar lies in a rich galaxy field. Loose groups of galaxies are present in the field at <z_1_> = 0.1669 and <z_2_> =…
An Occultation by Saturn's Rings on 1991 October 2-3 Observed With The Hubble Space Telescope
Bosh, A. S.; Dolan, J. F.; Nelson, M. J. +7 more
An occultation of the star GSC 6323-01396 (V = 11.9) by Saturn's rings was observed with the High-Speed Photometer on the Hubble Space Telescope (HST) on 1991 October 2-3. This occultation occurred when Saturn was near a stationary point, so the apparent motion of Saturn relative to the star was dominated by the HST orbital motion (8 km/s). Data w…
Hubble Space Telescope Imaging of Herbig-Haro Object No. 2
Schultz, A. S. B.; Raymond, John C.; Dopita, Michael A. +6 more
Images of Herbig-Haro Object No. 2 obtained with the Planetary Camera of the Hubble Space Telescope are presented and discussed. The images, obtained in the emission lines of H-alpha, forbidden S II, and forbidden O III at a scale of 0.044 arcsec/pixel, have been registered to within 11 milliarcsec, and the spherically aberrated images have been r…