Search Publications
An Evolutionary Turbulent Model of Saturn's Subnebula: Implications for the Origin of the Atmosphere of Titan
Mousis, Olivier; Gautier, Daniel; Bockelée-Morvan, Dominique
We have elaborated an evolutionary turbulent model of the subnebula of Saturn derived from that of Dubrulle (1993, Icarus106, 59-76) for the solar nebula, which is valid for a geometrically thin disk. We demonstrate that if carbon and nitrogen were in the form of CO and N 2, respectively, in the early subnebula, these molecules were not…
Photometry of Mercury from SOHO/LASCO and Earth. The Phase Function from 2 to 170 deg.
Howard, Russell A.; Mallama, Anthony; Wang, Dennis
CCD observations of Mercury were obtained with the large angle spectrometric coronograph (LASCO) on the solar and heliospheric observatory spacecraft, near superior and inferior solar conjunctions. Whole disk photometry was extracted from the orange and blue filter images and transformed to V magnitudes on the UBV system. The LASCO data were combi…
The Origin of Water Vapor and Carbon Dioxide in Jupiter's Stratosphere
Lellouch, E.; Encrenaz, T.; Feuchtgruber, H. +6 more
Observations of H 2O rotational lines from the Infrared Space Observatory (ISO) and the Submillimeter Wave Astronomy Satellite (SWAS) and of the CO 2 ν 2 band by ISO are analyzed jointly to determine the origin of water vapor and carbon dioxide in Jupiter's stratosphere. Simultaneous modelling of ISO/LWS and ISO/SW…
Sungrazing Comets Discovered with the SOHO/LASCO Coronagraphs 1996-1998
Llebaria, A.; St. Cyr, O. C.; Lamy, P. +2 more
The Kreutz sungrazing family of comets is unique because of its small perihelion distance and because of the large number of known members of this family. SOHO/LASCO coronagraph observations beginning in 1996 have revealed an unprecedented number of Kreutz comets. These new coronagraph observations improve upon earlier observations because of a la…
Transition from Gaseous Compounds to Aerosols in Titan's Atmosphere
McKay, Christopher P.; Lebonnois, Sébastien; Bakes, E. L. O.
We investigate the chemical transition of simple molecules like C 2H 2 and HCN into aerosol particles in the context of Titan's atmosphere. Experiments that synthesize analogs (tholins) for these aerosols can help illuminate and constrain these polymerization mechanisms. Using information available from these experiments, we …
Dust Grains in the Comae and Tails of Sungrazing Comets: Modeling of Their Mineralogical and Morphological Properties
Kimura, Hiroshi; Mann, Ingrid; Jessberger, Elmar K. +1 more
Observations of sungrazing comets, all of which belong to the Kreutz family, provide the opportunity of studying the properties of dust in the comae and tails of the comets. On the basis of available information on cometary and interplanetary dust as well as observations of dust in the tails of sungrazers, we model dust in sungrazing comets as flu…
New Observational Results Concerning Jupiter's Great Red Spot
Achterberg, Richard K.; Flasar, F. Michael; Simon-Miller, Amy A. +4 more
The changing size and aspect ratio of the Great Red Spot from 1880 to 2000 are reviewed, indicating that the length of the system has decreased significantly over the last 100 years and continues to decrease at present at a rate of 0.19 degrees per year. Voyager IRIS maps of para hydrogen fraction and potential temperature over the system are pres…
Saturn's F Ring: Kinematics and Particle Sizes from Stellar Occultation Studies
Nicholson, P. D.; Bosh, A. S.; Olkin, C. B. +1 more
The occultation of GSC5249-01240 by Saturn's rings was observed in a spectrally resolved mode using the Faint Object Spectrograph on the Hubble Space Telescope. By combining these data with other occultation data, we have determined the inclination of the F ring to be 0.0065±0.0014 deg. Our inclined F ring orbit model explains an abrupt decrease i…
The Nucleus of Comet 22P/Kopff and Its Inner Coma
Jorda, L.; Lamy, P. L.; A'Hearn, M. F. +3 more
We report the detection of the nucleus of Comet 22P/Kopff with the Planetary Camera of the Hubble Space Telescope (HST) and with the Infrared Camera of the Infrared Space Observatory (ISOCAM). The HST observations were performed on 18 July 1996, 16 days after its perihelion passage of 2 July 1996, when it was at Rh=1.59 AU from the Sun …
HST Multicolor (255-1042 nm) Photometry of Saturn's Main Rings. I: Radial Profiles, Phase and Opening Angle Variations, and Regional Spectra
French, Richard G.; Dones, Luke; Cuzzi, Jeffrey N.
The main rings of Saturn were observed with the Planetary Camera of the WFPC2 instrument on the Hubble Space Telescope (HST) from September 1996 to December 2000 as the ring opening angle to Earth and Sun increased from 4° to 24°, with a spread of phase angles between 0.3° and 6° at each opening angle. The rings were routinely observed in the five…