Search Publications
Tidal dissipation within large icy satellites: Applications to Europa and Titan
Sotin, C.; Tobie, G.; Mocquet, A.
This paper describes a new approach based on variational principles to calculate the radial distribution of tidal energy dissipation in any satellite. The advantage of the model with respect to classical solutions, is that it relates in a straightforward way the radial distribution of the time-averaged dissipation rate to its sensitivity to the co…
Titan's internal structure inferred from a coupled thermal-orbital model
Sotin, Christophe; Lunine, Jonathan I.; Tobie, Gabriel +2 more
Through coupled thermal and orbital calculations including a full description of tidal dissipation, heat transfer and the H 2O sbnd NH 3 phase diagram, we propose a model for the internal structure and composition of Titan testable with Cassini-Huygens measurements. The high value of Titan's orbital eccentricity provides a st…
Possibilities for methanogenic life in liquid methane on the surface of Titan
McKay, C. P.; Smith, H. D.
Photochemically produced compounds on Titan, principally acetylene, ethane and organic solids, would release energy when consumed with atmospheric hydrogen, at levels of 334, 57, and 54 kJ mol -1, respectively. On Earth methanogenic bacteria can survive on this energy level. Here we speculate on the possibility of widespread methanogeni…
Nucleus properties of Comet 67P/Churyumov Gerasimenko estimated from non-gravitational force modeling
Gutiérrez, Pedro J.; Davidsson, Björn J. R.
By considering model comet nuclei with a wide range of sizes, prolate ellipsoidal shapes, spin axis orientations, and surface activity patterns, constraints have been placed on the nucleus properties of the primary Rosetta target, Comet 67P/Churyumov-Gerasimenko. This is done by requiring that the model bodies simultaneously reproduce the empirica…
A spectroscopic study of the surfaces of Saturn's large satellites: H 2O ice, tholins, and minor constituents
Emery, Joshua P.; Cruikshank, Dale P.; Owen, Tobias C. +7 more
We present spectra of Saturn's icy satellites Mimas, Enceladus, Tethys, Dione, Rhea, and Hyperion, 1.0-2.5 µm, with data extending to shorter (Mimas and Enceladus) and longer (Rhea and Dione) wavelengths for certain objects. The spectral resolution ( R=λ/Δλ) of the data shown here is in the range 800-1000, depending on the specific instrumen…
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 …
Thermal infrared (8 13 µm) spectra of 29 asteroids: the Cornell Mid-Infrared Asteroid Spectroscopy (MIDAS) Survey
Bell, James F.; Hayward, Thomas L.; Lim, Lucy F. +1 more
We report the results of the Cornell Mid-IR Asteroid Spectroscopy (MIDAS) survey, a program of ground-based observations designed to characterize the 8-13 µm spectral properties of a statistically significant sample of asteroids from a wide variety of visible to near-IR spectral classes. MIDAS is conducted at Palomar Observatory using the Sp…
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…