Search Publications
An updated rotation model for Comet 9P/Tempel 1
Li, J. -Y.; Harris, A. W.; Veverka, J. +8 more
Observations from the second encounter of Comet 9P/Tempel 1 by the Stardust-NExT spacecraft provide an improved shape model and rotational pole for the nucleus (Thomas, P.C. et al. [2012]. Icarus 222, 453-466) that allows us to greatly improve our knowledge of its rotational evolution beyond that outlined earlier in Belton et al. (Belton, M.J.S. e…
Probing the inner boundaries of Saturn's A ring with the Iapetus -1:0 nodal bending wave
Porco, Carolyn C.; Hedman, Matthew M.; Burns, Joseph A. +2 more
The Iapetus -1:0 nodal bending wave, the first spiral wave ever described in Saturn's rings, has been seen again for the first time in 29 years. We demonstrate that it is in fact the nodal bending wave, not the 1:0 apsidal density wave as previously reported. We use wavelet analysis to determine the wavelength profile, thus deriving the surface de…
Valleys in pit craters on Mars: Characteristics, distribution, and formation mechanisms
Fassett, Caleb I.; Peel, Samantha E.
New observations of central pit craters on Mars reveal that some craters contain prominent interior valley networks that drain into their central pit. In this study, we catalog the distribution of pit craters with associated valleys, and characterize in detail five diverse, well-preserved examples. In some instances, sedimentary deposits we interp…
The characteristics of the O2 Herzberg II and Chamberlain bands observed with VIRTIS/Venus Express
Drossart, P.; Piccioni, G.; Soret, L. +6 more
The oxygen Venus nightglow emissions in the visible spectral range have been known since the early observations from the Venera spacecraft. Recent observations with the VIRTIS instrument on board Venus Express allowed us to re-examine the Herzberg II system of O2 and to further study its vertical distribution, in particular the (0-ν″ wi…
HMT production and sublimation during thermal process of cometary organic analogs. Implications for its detection with the ROSETTA instruments
Cottin, Hervé; Fray, Nicolas; Benilan, Yves +3 more
One important component of refractory organic residues synthesized from interstellar/cometary ice analogues is hexamethylenetetramine (HMT, C6H12N4). However, HMT has never been observed in any astrophysical or planetary environment so far. We investigated thermal evolution of HMT above ambient temperature. The syn…
Scattering properties of Saturn's rings in the far ultraviolet from Cassini UVIS spectra
Colwell, Joshua E.; Esposito, Larry W.; Bradley, E. Todd
We use Cassini UVIS data to determine the scattering properties of Saturn's ring particles in the FUV. We have replaced the scattering function from the classical Chandrasekhar single scattering radiative transfer equation for reflectance with a ring wake model for the A and B rings derived from stellar occultations. The free parameters in this mo…
Venus Express observations of ULF and ELF waves in the Venus ionosphere: Wave properties and sources
Russell, C. T.; Wei, H. Y.; Zhang, T. L. +3 more
Electrical activity in a planetary atmosphere enables chemical reactions that are not possible under conditions of local thermodynamic equilibrium. In both the Venus and terrestrial atmospheres, lightning forms nitric oxide. Despite the existence of an inventory of NO at Venus like the Earth’s, and despite observations of the signals expected from…
The opposition effect in Saturn’s main rings as seen by Cassini ISS: 1. Morphology of phase functions and dependence on the local optical depth
Déau, Estelle; Dones, Luke; Charnoz, Sébastien +4 more
During the Prime mission (2004-2008), the Cassini cameras captured the opposition effect in Saturn’s main rings with a fine radial resolution at extremely small phase angles. Phase functions were extracted for 211 different radial locations in the main ring system (135 in the broadband clear filter of the Wide Angle Camera at 635 nm, 76 in four na…
Upper limits for PH3 and H2S in Titan's atmosphere from Cassini CIRS
Nixon, Conor A.; Irwin, Patrick G. J.; Teanby, Nicholas A. +1 more
We have searched for the presence of simple P and S-bearing molecules in Titan's atmosphere, by looking for the characteristic signatures of phosphine and hydrogen sulfide in infrared spectra obtained by Cassini CIRS. As a result we have placed the first upper limits on the stratospheric abundances, which are 1 ppb (PH3) and 330 ppb (H<…
Earliest recorded ground-based decameter wavelength observations of Saturn's lightning during the giant E-storm detected by Cassini spacecraft in early 2006
Gurnett, D. A.; Kurth, W. S.; Rucker, H. O. +12 more
We report the history of the first recorded ground-based radio detection of Saturn's lightning using the Ukrainian UTR-2 radiotelescope at frequencies from 20 to 25 MHz. The observations were performed between 29 January and 3 February 2006, during which lighting activity (E-storm) on Saturn was detected by the radio experiment onboard Cassini spa…