Search Publications
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…
Patterned ground in martian high northern latitudes: Morphology and age constraints
Korteniemi, J.; Kreslavsky, M. A.
We performed a systematic survey of typical surface patterns and small (5-50 m) impact craters in a zone between 50° and 70° latitude in the Northern Lowlands of Mars. We found that small-scale (<10 m) polygonal pattern formed by narrow fractures is typical in the northern half of the studied zone. We interpret this pattern to be formed by acti…
Comparative analysis of airglow emissions in terrestrial planets, observed with VIRTIS-M instruments on board Rosetta and Venus Express
Piccioni, G.; Capaccioni, F.; Gérard, J. -C. +3 more
Airglow emissions are optimal processes to investigate the chemistry and dynamics in planetary atmospheres. In this study, we focus on the O2 and OH airglow emissions in Venus, Earth, and Mars atmospheres, which are controlled by chemical reactions common to the three planets. By studying these phenomena on Venus, Earth, and Mars using …
Temperature and variability of Pillan, Wayland Patera, and Loki Patera on Io from Cassini ISS data
Radebaugh, Jani; Stephens, Denise C.; Allen, Daniel R.
Cassini spacecraft images of Io obtained during its flyby of Jupiter in late 2000 and early 2001 were used to determine the lava composition and eruption style of three faint hot spots, Pillan, Wayland Patera, and Loki Patera. We found a maximum color temperature of 1130 ± 289 K for Pillan and maximum color temperatures of 1297 ± 289 K and 1387 ± …
Age and evolution of the lower NW flank of the Hecates Tholus volcano, Mars, based on crater size-frequency distribution on CTX images
Michael, G. G.; de Pablo, M. A.; Centeno, J. D.
We present results of crater size-frequency distribution (SFD) analysis of the lower NW flank of the Hecates Tholus volcano, Elysium volcanic province of Mars, by the use of images acquired by the Context (CTX) instrument on board of Mars Reconnaissance Orbiter (6 m/pixel in resolution). Previous similar works were focused on the caldera complex o…
Comparison of general circulation model atmospheric wave simulations with wind observations of venusian mesosphere
Aoki, Shohei; Kasaba, Yasumasa; Nakagawa, Hiromu +5 more
Simulations from our venusian general circulation model (GCM) forcing the presence of planetary-scale waves and mesoscale gravity waves were compared with infrared (IR) heterodyne observations of Doppler wind velocities in the venusian mesospheric altitude region (110 km). Observations confirmed the strong short-term variations in the venusian mes…
Titan's Xanadu region: Geomorphology and formation scenario
Lunine, Jonathan I.; Mitri, Giuseppe; Langhans, Migrjam
Based on comprehensive mapping of the region, the recent theories of Xanadu's origin are examined and a chronology of geologic processes is proposed. The geologic history of Titan's Xanadu region is different from that of the other surface units on Saturn's moon. A previously proposed origin of western Xanadu from a giant impact in the early histo…