Search Publications
Collisional evolution of the asteroid belt
Cheng, Andrew F.
A new synthesis of asteroid collisional evolution is motivated by the question of whether most asteroids larger than ∼1 km size are strengthless gravitational aggregates (rubble piles). NEAR found Eros not to be a rubble pile, but a shattered collisional fragment, with a through-going fracture system, and an average of about 20 m regolith cover. O…
Saturn's cloud morphology and zonal winds before the Cassini encounter
Hueso, R.; Sánchez-Lavega, A.; Rojas, J. F. +2 more
Analyses of Hubble Space Telescope (HST) images of Saturn obtained from August 2003 to March 2004, with extensive support from ground-based telescopes, have been used to characterize the cloud morphology and motions in its atmosphere few months before the Cassini encounter. We present data on the major meteorological features as potential targets …
The jovian rings: new results derived from Cassini, Galileo, Voyager, and Earth-based observations
Nicholson, P. D.; Burns, J. A.; Showalter, M. R. +3 more
Cassini's Imaging Science Subsystem (ISS) instrument took nearly 1200 images of the Jupiter ring system during the spacecraft's 6-month encounter with Jupiter (Porco et al., 2003, Science 299, 1541-1547). These observations constitute the most complete data set of the ring taken by a single instrument, both in phase angle (0.5°-120° at seven angle…
Relative contributions of sublimation and volcanoes to Io's atmosphere inferred from its plasma interaction during solar eclipse
Saur, Joachim; Strobel, Darrell F.
We present a model that describes Io's delayed electrodynamic response to a temporal change in Io's atmosphere. Our model incorporates the relevant physical processes involved in Io's atmosphere-ionosphere-magnetosphere electrodynamic interaction to predict the far-ultraviolet (FUV) radiation as Io enters Jupiter's shadow and re-emerges into sunli…
Jovian auroral spectroscopy with FUSE: analysis of self-absorption and implications for electron precipitation
Feldman, P. D.; Moos, H. W.; Roueff, E. +12 more
High-resolution ( ∼0.22 Å) spectra of the north jovian aurora were obtained in the 905-1180 Å window with the Far Ultraviolet Spectroscopic Explorer (FUSE) on October 28, 2000. The FUSE instrument resolves the rotational structure of the H 2 spectra and the spectral range allows the study of self-absorption. Below 1100 Å, transitions co…
Titan's surface and rotation: new results from Voyager 1 images
McEwen, Alfred; Lorenz, Ralph D.; Richardson, James
We present an analysis of images of Saturn's moon Titan, obtained by the Voyager 1 spacecraft on November 8-12, 1980. Orange filter (590-640 nm) images were photometrically corrected and a longitudinal average removed from them, leaving residual images with up to 5% contrast, and dominated by surface reflectivity. The resultant map shows the same …
Evidence for temporal change at Uranus' south pole
Hammel, H. B.; Rages, K. A.; Friedson, A. J.
Analysis of Hubble Space Telescope images of Uranus taken between 1994 and 2002 shows evidence for temporal changes in zonal brightness patterns in the south polar region. Between 1994 and 2002, a relatively bright ring developed near 70° S. The pole itself, which was the brightest area of the southern hemisphere in 1994, has become relatively dar…
Study of the vertical structure of Saturn's atmosphere using HST/WFPC2 images
Moreno, F.; Grodent, D.; Dols, V. +3 more
We have studied the vertical structure of hazes at six different latitudes (-60°, -50°, -30°, -10°, +30°, and +50°) on Saturn's atmosphere. For that purpose we have compared the results of our forward radiative transfer model to limb-to-limb reflectivity scans at four different wavelengths (230, 275, 673.2, and 893 nm). The images were obtained wi…
Orbits and masses of Saturn's coorbital and F-ring shepherding satellites
French, Richard G.; Jacobson, Robert A.
We have obtained numerically integrated orbits for Saturn's coorbital satellites, Janus and Epimetheus, together with Saturn's F-ring shepherding satellites, Prometheus and Pandora. The orbits are fit to astrometric observations acquired with the Hubble Space Telescope and from Earth-based observatories and to imaging data acquired from the Voyage…
The UV environment of the Beagle 2 landing site: detailed investigations and detection of atmospheric state
Zarnecki, John C.; Cockell, Charles S.; Patel, Manish R. +2 more
December 25th 2003 will see the Beagle 2 lander arrive at the surface of Mars in the Isidis region, allowing for the first time in situ measurements of ultraviolet (UV) flux directly from the surface of Mars through the use of a sensor designed as part of a miniaturised environmental package. The expected conditions the sensor will experience are …