Search Publications
Saturn's cloud structure and temporal evolution from ten years of Hubble Space Telescope images (1994 2003)
Sánchez-Lavega, A.; Rojas, J. F.; Pérez-Hoyos, S. +1 more
We present a study of the vertical structure of clouds and hazes in the upper atmosphere of Saturn's Southern Hemisphere during 1994-2003, about one third of a Saturn year, based on Hubble Space Telescope images. The photometrically calibrated WFPC2 images cover the spectral region between the near-UV (218-255 nm) and the near-IR (953-1042 nm), in…
Saturn's vertical and latitudinal cloud structure 1991 2004 from HST imaging in 30 filters
Karkoschka, Erich; Tomasko, Martin
We analyzed 134 images of Saturn taken by the Hubble Space Telescope between 1991 and 2004. The images cover wavelengths between 231 and 2370 nm in 30 filters. We combined some 10 million calibrated reflectivity measurements into 18,000 center-to-limb curves. We used the method of principal component analysis to find the main latitudinal and tempo…
Mid-infrared detection of large longitudinal asymmetries in Io's SO 2 atmosphere
Lellouch, Emmanuel; Spencer, John R.; Richter, Matthew J. +4 more
We have observed about 16 absorption lines of the ν SO 2 vibrational band on Io, in disk-integrated 19-µm spectra taken with the TEXES high spectral resolution mid-infrared spectrograph at the NASA Infrared Telescope Facility in November 2001, December 2002, and January 2004. These are the first ground-based infrared observations …
The opposition surge of Enceladus: HST observations 338-1022 nm
French, Richard G.; Verbiscer, Anne J.; McGhee, Colleen A.
Hubble Space Telescope (HST) Wide-Field Planetary Camera (WFPC2) observations at phase angles in the range α=0.26°-6.4° obtained at every opposition and near quadrature between October 1996 and December 2002 reveal the opposition effect of Enceladus. We present a photometric analysis of nearly 200 images obtained through the five broadband UVBRI f…
Cassini UVIS observations of Europa's oxygen atmosphere and torus
Hendrix, A. R.; Shemansky, Donald E.; Hansen, Candice J.
Observations of the Europa environment using the Cassini UltraViolet Imaging Spectrograph (UVIS) show the presence of an extended atomic oxygen atmosphere in addition to the bound molecular oxygen atmosphere first detected by Hubble Space Telescope in 1994 [D.T. Hall, D.F. Strobel, P.D. Feldman, M.A. McGrath, H.A. Weaver, 1995, Detection of an oxy…
Diverse albedos of small trans-neptunian objects
Grundy, W. M.; Noll, K. S.; Stephens, D. C.
Discovery of trans-neptunian object (TNO) satellites and determination of their orbits has recently enabled estimation of the size and albedo of several small TNOs, extending the size range of objects having known size and albedo down into the sub-100 km range. In this paper we compute albedo and size estimates or limits for 20 TNOs, using a consi…
Dynamics of cloud features on Uranus
Sromovsky, L. A.; Fry, P. M.
Near-infrared adaptive optics imaging of Uranus by the Keck 2 telescope during 2003 and 2004 has revealed numerous discrete cloud features, 70 of which were used to extend the zonal wind profile of Uranus up to 60° N. We confirmed the presence of a north-south asymmetry in the circulation [Karkoschka, E., 1998. Science 280, 570-572], and improved …
Uranus in 2003: Zonal winds, banded structure, and discrete features
Hammel, H. B.; de Pater, I.; Gibbard, S. +2 more
Imaging of Uranus in 2003 with the Keck 10-m telescope reveals banded zonal structure and dozens of discrete cloud features at J and H bands; several features in the northern hemisphere are also detectable at K'. By tracking features over four days, we extend the zonal wind profile well into the northern hemisphere. We report the first measurement…
Radar imaging of Saturn's rings
Nicholson, Philip D.; French, Richard G.; Campbell, Donald B. +4 more
We present delay-Doppler images of Saturn's rings based on radar observations made at Arecibo Observatory between 1999 and 2003, at a wavelength of 12.6 cm and at ring opening angles of 20.1°⩽|B|⩽26.7°. The average radar cross-section of the A ring is ∼77% relative to that of the B ring, while a stringent upper limit of 3% is placed on the cross-s…
Cassini UVIS observations of Jupiter's auroral variability
Dougherty, Michele K.; West, Robert A.; Gurnett, Donald A. +20 more
The Cassini spacecraft Ultraviolet Imaging Spectrograph (UVIS) obtained observations of Jupiter's auroral emissions in H 2 band systems and H Lyman- α from day 275 of 2000 (October 1), to day 81 of 2001 (March 22). Much of the globally integrated auroral variability measured with UVIS can be explained simply in terms of the rotation of …