Search Publications
The hydrogen ortho-to-para ratio in the stratospheres of the giant planets
Lellouch, Emmanuel; Fouchet, Thierry; Feuchtgruber, Helmut
Observations of the H 2 S(0) and S(1) quadrupole lines in the four giant planets by the short-wavelength spectrometer of the Infrared Space Observatory are analyzed. These lines probe pressure levels located between 10 and 1 mbar and allow us to determine the stratospheric hydrogen para fraction for the first time. In Jupiter and Saturn…
Neptune's far-infrared spectrum from the ISO long-wavelength and short-wavelength spectrometers
Swinyard, Bruce M.; Orton, Glenn S.; Feuchtgruber, Helmut +4 more
Neptune was observed by the Infrared Space Observatory (ISO) Long-Wavelength Spectrometer (LWS) between 46 and 185 µm. At wavelengths between 50 and 110 µm the accuracy of these measurements is ⩽0.3 K. Observations of this planet made by the ISO Short-Wavelength Spectrometer between 28 and 44 µm were combined with the LWS data to…
Photometry of pluto in the last decade and before: evidence for volatile transport?
Buratti, B. J.; Heinze, A.; Young, J. +7 more
Photometric observations of Pluto in the BVR filter system were obtained in 1999 and in 1990-1993, and observations in the 0.89-µm methane absorption band were obtained in 2000. Our 1999 observations yield lightcurve amplitudes of 0.30 ± 0.01, 0.26 ± 0.01, and 0.21 ± 0.02 and geometric albedos of 0.44 ± 0.04, 0.52 ± 0.03, and 0.58 ± 0.02 in …
The dynamics of jovian white ovals from formation to merger
Marcus, Philip S.; Youssef, Ashraf
In early 1998 two of the three, long-lived anticyclonic, jovian white ovals merged. In 2000 the two remaining white ovals merged into one. Here we examine that behavior, as well as the dynamics of three earlier epochs: the Formation Epoch (1939-1941), during which a nearly axisymmetric band broke apart to form the vortices; the Kármán Vortex Stree…
The mass ratio of Charon to Pluto from Hubble Space Telescope astrometry with the fine guidance sensors
Olkin, C. B.; Franz, O. G.; Wasserman, L. H.
The mass ratio of Charon to Pluto is a basic parameter describing the binary system and is necessary for determining the individual masses and densities of these two bodies. Previous measurements of the mass ratio have been made, but the solutions differ significantly (Null et al., 1993; Young et al., 1994; Null and Owen, 1996; Foust et al., 1997;…
EPIC simulations of the merger of Jupiter's White Ovals BE and FA: altitude-dependent behavior
Dowling, Timothy E.; Sánchez-Lavega, Agustín.; Morales-Juberías, Raúl
Observations of the merger of Jupiter's White Ovals BE and FA show altitude-dependent behavior that we seek to capture in numerical simulations. In particular, it was observed that the upper portions of the vortices orbited each other before merging, but the lower portions translated into each other without orbiting, a phenomenon we term the pair-…
Impact of aerosols present in Titan's atmosphere on the CASSINI radar experiment
Rodriguez, S.; Encrenaz, P.; Dobrijevic, M. +4 more
Simulations of Titan's atmospheric transmission and surface reflectivity have been developed in order to estimate how Titan's atmosphere and surface properties could affect performances of the Cassini radar experiment. In this paper we present a selection of models for Titan's haze, vertical rain distribution, and surface composition implemented i…
A study of the propagation of electromagnetic waves in Titan's atmosphere with the TLM numerical method
Morente, Juan A.; Portí, Jorge A.; Besser, Bruno P. +2 more
A numerical modeling of the electromagnetic characteristics of Titan's atmosphere is carried out by means of the TLM numerical method, with the aim of calculating the Schumann resonant frequencies of Saturn's satellite. The detection and measurement of these resonances by the Huygens probe, which will enter Titan's atmosphere at the beginning of 2…
The nature of Neptune's increasing brightness: evidence for a seasonal response *
Baines, K. H.; Sromovsky, L. A.; Fry, P. M. +1 more
Hubble Space Telescope (HST) observations in August 2002 show that Neptune's disk-averaged reflectivity increased significantly since 1996, by 3.2 ± 0.3% at 467 nm, 5.6 ± 0.6% at 673 nm, and 40 ± 4% in the 850-1000 nm band, which mainly results from dramatic brightness increases in restricted latitude bands. When 467-nm HST observations from 1994 …
Vesta's UV lightcurve: hemispheric variation in brightness and spectral reversal
Vilas, Faith; Hendrix, Amanda R.; Festou, Michel C.
Spectra of asteroid 4 Vesta obtained in October 1990 with the International Ultraviolet Explorer are reanalyzed and reinterpreted. A large portion of the eastern hemisphere (based on the prime meridian definition of Thomas et al., 1997a) is darker at UV wavelengths than much of the western hemisphere. The UV lightcurve is in contrast with the visi…