Search Publications
Sporadic formation of slope streaks on Mars
Schorghofer, Norbert; King, Christina M.
Slope streaks are a form of gravity-driven mass-movements that frequently occur on Mars today. The cause of slope streak formation remains unclear; both, dry and wet processes have been suggested. Here, we observationally constrain the time of the year during which slope streaks form. Imagery from four Mars-orbiting cameras is mined to identify lo…
The martian mesosphere as revealed by CO 2 cloud observations and General Circulation Modeling
González-Galindo, Francisco; Määttänen, Anni; Forget, François +1 more
Different missions have observed mesospheric clouds on Mars in the last years. The presence of these clouds implies, among other conditions, mesospheric temperatures below CO 2 condensation temperature. We use a General Circulation Model to study the mesospheric temperatures and compare the observed distribution of the mesospheric cloud…
Distribution of HCN in Titan's upper atmosphere from Cassini/VIMS observations at 3 µm
López-Puertas, M.; D'Aversa, E.; García-Comas, M. +5 more
Cassini/VIMS limb observations have been used to retrieve vertical profiles of hydrogen cyanide (HCN) from its 3 µm emission in the region from 600 to 1100 km altitude at daytime. While the daytime emission is large up to about 1100 km, it vanishes at nighttime at very low altitudes, suggesting that the daytime emission originates under non-…
Vertical structure of Jupiter's Oval BA before and after it reddened: What changed?
de Pater, Imke; Wong, Michael H.; Marcus, Philip S. +2 more
To constrain the properties of Oval BA before and after it reddened, we use Hubble methane band images from 1994 to 2009 to find that the distribution of upper tropospheric haze atop the oval and its progenitors remained unchanged, with reflectivity variations of less than 10% over this time span. We quantify measurement uncertainties and short-te…
Changes in Jupiter’s zonal velocity between 1979 and 2008
de Pater, Imke; Wong, Michael H.; Marcus, Philip S. +1 more
We show that the peak velocity of Jupiter's visible-cloud-level zonal winds near 24°N (planetographic) increased from 2000 to 2008. This increase was the only change in the zonal velocity from 2000 to 2008 for latitudes between ±70° that was statistically significant and not obviously associated with visible weather. We present the first automated…
Wave constraints for Titan’s Jingpo Lacus and Kraken Mare from VIMS specular reflection lightcurves
Nicholson, Philip D.; Sotin, Christophe; Barnes, Jason W. +10 more
Stephan et al. (Stephan, K. et al. [2010]. Geophys. Res. Lett. 37, 7104-+.) first saw the glint of sunlight specularly reflected off of Titan's lakes. We develop a quantitative model for analyzing the photometric lightcurve generated during a flyby in which the specularly reflected light flux depends on the fraction of the solar specular footprint…
Half-widths, their temperature dependence, and line shifts for the HDO-CO 2 collision system for applications to CO 2-rich planetary atmospheres
Gamache, Robert R.; Laraia, Anne L.; Lamouroux, Julien
Measurements of water vapor in the atmospheres of Venus or Mars by spectroscopic techniques in the infrared range are being made routinely by instruments onboard the Venus Express and the Mars Reconnaissance Orbiter. The interpretation of these measurements in the 2250-4450 cm -1 region is being complicated by the presence of HDO lines …
Lunar X-ray fluorescence observations by the Chandrayaan-1 X-ray Spectrometer (C1XS): Results from the nearside southern highlands
Grande, M.; Alha, L.; Huovelin, J. +19 more
The Chandrayaan-1 X-ray Spectrometer (C1XS) flown on-board the first Indian lunar mission Chandrayaan-1, measured X-ray fluorescence spectra during several episodes of solar flares during its operational period of ∼9 months. The accompanying X-ray Solar Monitor (XSM) provided simultaneous spectra of solar X-rays incident on the Moon which are esse…
Obliquity tides do not significantly heat Enceladus
Nimmo, F.; Chen, E. M. A.
Recently, Tyler [Tyler, R.H., 2009. Geophys. Res. Lett. 36, L15205; Tyler, R., 2011. Icarus, 211, 770-779] proposed that the tide due to an obliquity of greater than 0.1° might drive resonant flow in a liquid ocean at Enceladus, and that dissipation of the ocean's kinetic energy may be an alternate source for the observed global heat flux. While t…
Evidence for episodic alluvial fan formation in far western Terra Tyrrhena, Mars
Chojnacki, Matthew; Williams, Rebecca M. E.; Seelos, Kimberly D. +4 more
A Late Noachian-aged alluvial fan complex within Harris Crater in far western Terra Tyrrhena, Mars, is comprised of two well-defined source regions and associated discrete depositional lobes. Three fan units were recognized based on common morphological characteristics, thermal properties and spectral signatures. Although the entire fan complex ha…