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Sulfur Dioxide in the Atmosphere of Venus. II. Modeling Results
Esposito, L. W.; Barth, C. A.; McClintock, W. E. +1 more
We have analyzed the results from the UV sounding rocket observations of Venus made on 15 September 1988 and 29 March 1991 which obtained high-resolution spectra of Venus clouds from 199 to 230 nm. The albedo of Venus in this wavelength range is dominated by absorption features of sulfur dioxide and sulfur monoxide. We estimate that the mixing rat…
Disk-Resolved Imaging of Io with the Hubble Space Telescope
McGrath, Melissa A.; Paresce, Francesco; Sartoretti, Paola
The first disk-resolved image of Io's trailing hemisphere in the ultraviolet, as well as a visible image of the same hemisphere, has been obtained with the Faint Object Camera (FOC) of the Hubble Space Telescope on March 15, 1992, at a resolution of 210 km. Io shows no large-scale changes in the visible over the 13 years elapsed since the last dis…
Ultraviolet Spectra and Geometric Albedos of 45 Asteroids
Buratti, B. J.; Roettger, E. E.
Spectral reflectances and geometric albedos between 2300 and 3250 Å are determined for 45 asteroids from data acquired by the International Ultraviolet Explorer satellite. The geometric albedos are consistently tow, ranging from ∼0.02 for C-type asteroids to ∼0.08 for M-type asteroids. An exception is the single E-type asteroid (44 Nysa) with a ge…
Dynamical and Observational Constraints on Satellites in the Inner Pluto-Charon System
Stern, S. Alan; Levison, Harold F.; Duncan, Martin J. +2 more
It is not known if Pluto has other satellites besides its massive partner Charon. In the past, searches for additional satellites in the Pluto-Charon system have extended from the Solar-tidal stability boundary (≈90 arcsec from Pluto) inward to about 1 arcsec from Pluto. Here we further explore the inner (i.e., <10 arcsec) region of the Pluto-C…
The Nature of the Source of CO in Comet P/Halley
Samarasinha, Nalin H.; Belton, Michael J. S.
We show by numerical simulations that the CO distribution in the coma of Comet P/Halley as measured by neutral gas mass spectrometer aboard Giotto spacecraft (P. Eberhardt et al., 1987, Astron, Astrophys, 187, 481-484) can be explained by an extended jet source originating from vent 1 in the rotational model of M. J. S. Belton et al. (1991, Icarus…
A Hubble Space Telescope Study of Posteclipse Brightening and Albedo Changes on Io
Secosky, James J.; Potter, Michael
Images of Io taken by the Hubble Space Telescope Planetary Camera using filters at 7120 and 3577 Å in April and May 1992 shortly after Io emerged from Jupiter's shadow have been analyzed for the effect of posteclipse brightening first reported by Binder and Cruikshank (1964, Icarus 3,299-305). The classic effect displays a 10% increase in brighten…
The Ultraviolet Spectrum of Triton from HST: First Results
Stern, S. Alan; Trafton, Laurence M.
We report on the first Hubble Space Telescope (HST) spectra of Neptune's largest satellite, Triton. The spectra were taken on 16-17 May 1992 by the HST Faint Object Spectrograph. They span the region 2220-3278 Å. This overlaps IUE spectra of Triton we obtained, 2700-3100 Å, and penetrates the region from 2220 to 2550 A for the first time. The deri…
Observational Constraints on the Lifetime of Cometary H 2O
Cochran, Anita L.; Schleicher, David G.
We used a carefully selected set of observations of five comets along with a vectorial model and the Haser model to explore the lifetimes against photodissociation of H2O and OH in cometary comae. The photometric and long-slit CCD data described in this paper were obtained specifically for this project, while the IUE data are archival. …
Saturn's Upper Atmospheric Hazes Observed by the Hubble Space Telescope
Karkoschka, Erich; Tomasko, Martin G.
We observed Saturn with the Hubble Space Telescope at wavelengths 0.30-0.89 µm for the purpose of determining the distribution of hazes. In the stratosphere, haze optical depths in the ultraviolet are essentially zero for midnorthern latitudes, are small (∼0.2) at low latitudes and mid-southern latitudes, but large (almost unity) above 70° n…
Water Production Rates in Comet P/Halley from IUE Observations of HI Lyman-β
Feldman, Paul D.; Combi, Michael R.
During the 1985-1986 apparition of Comet P/Halley, the International Ultraviolet Explorer (IUE) satellite observed the comet using both the long-wavelength and short-wavelength spectrographs. The combination of a spherical radiative transfer model and the hybrid gas-dynamic/Monte Carlo model for hydrogen coma, which had been used to analyze H Lyma…