Search Publications
Bimodal distribution of sulfuric acid aerosols in the upper haze of Venus
Crisp, David; Zhang, Xi; Gao, Peter +2 more
Observations by the SPICAV/SOIR instruments aboard Venus Express have revealed that the upper haze (UH) of Venus, between 70 and 90 km, is variable on the order of days and that it is populated by two particle modes. We use a one-dimensional microphysics and vertical transport model based on the Community Aerosol and Radiation Model for Atmosphere…
Methane depletion in both polar regions of Uranus inferred from HST/STIS and Keck/NIRC2 observations
Sromovsky, L. A.; Fry, P. M.; Karkoschka, E. +3 more
From Space Telescope Imaging Spectrograph (STIS) observations of Uranus in 2012, when good views of its north polar regions were available, we found that the methane volume mixing ratio declined from about 4% at low latitudes to about 2% at 60-80°N. This depletion in the north polar region of Uranus in 2012 is similar in magnitude and depth to tha…
Plasma environment of a weak comet - Predictions for Comet 67P/Churyumov-Gerasimenko from multifluid-MHD and Hybrid models
Altwegg, K.; Glassmeier, K. -H.; Richter, I. +8 more
The interaction of a comet with the solar wind undergoes various stages as the comet's activity varies along its orbit. For a comet like 67P/Churyumov-Gerasimenko, the target comet of ESA's Rosetta mission, the various features include the formation of a Mach cone, the bow shock, and close to perihelion even a diamagnetic cavity. There are differe…
Mineral abundances at the final four curiosity study sites and implications for their formation
Poulet, F.; Bishop, J. L.; Carter, J. +2 more
A component of the landing site selection process for the Mars Science Laboratory (MSL) involved the presence of phyllosilicates as the main astrobiological targets. Gale crater was selected as the MSL landing site from among 4 down selected study sites (Gale, Eberswalde and Holden craters, Mawrth Vallis) that addressed the primary scientific goal…
Evidence for very recent melt-water and debris flow activity in gullies in a young mid-latitude crater on Mars
Hiesinger, H.; Hauber, E.; Johnsson, A. +2 more
Terrestrial debris flows and their deposits are mainly studied and monitored because of their hazardous nature. On Mars they may serve as geomorphologic indicators of transient liquid water. We compared the morphology of debris flow-like deposits within a young (∼0.2 Ma) mid-latitude crater on Mars with debris flow fans on Svalbard as possible ter…
Atmospheric thermal structure and cloud features in the southern hemisphere of Venus as retrieved from VIRTIS/VEX radiation measurements
Kappel, D.; Arnold, G.; Haus, R.
Thermal structure and cloud features in the atmosphere of Venus are investigated using spectroscopic nightside measurements recorded by the Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS) aboard ESA’s Venus Express mission in the moderate resolution infrared mapping channel (M-IR, 1-5 µm). New methodical approaches and retrieval r…
Mid-infrared spectroscopy of Uranus from the Spitzer infrared spectrometer: 2. Determination of the mean composition of the upper troposphere and stratosphere
Fletcher, Leigh N.; Moses, Julianne I.; Line, Michael R. +7 more
Mid-infrared spectral observations Uranus acquired with the Infrared Spectrometer (IRS) on the Spitzer Space Telescope are used to determine the abundances of C2H2, C2H6, CH3C2H, C4H2, CO2, and tentatively CH3 on Uranus at the time of the …
Cassini observations reveal a regime of zonostrophic macroturbulence on Jupiter
Read, Peter L.; Young, Roland M. B.; Armstrong, David +4 more
In December 2000, the Cassini fly-by near Jupiter delivered high-resolution images of Jupiter’s clouds over the entire planet in a band between 50°N and 50°S. Three daily-averaged two-dimensional velocity snapshots extracted from these images are used to perform spectral analysis of jovian atmospheric macroturbulence. A similar analysis is also pe…
Neptune at summer solstice: Zonal mean temperatures from ground-based observations, 2003-2007
de Pater, Imke; Fletcher, Leigh N.; Irwin, Patrick G. J. +3 more
Imaging and spectroscopy of Neptune's thermal infrared emission from Keck/LWS (2003), Gemini-N/MICHELLE (2005); VLT/VISIR (2006) and Gemini-S/TReCS (2007) is used to assess seasonal changes in Neptune's zonal mean temperatures between Voyager-2 observations (1989, heliocentric longitude Ls = 236 °) and southern summer solstice (2005, L<…
The dayside ionospheres of Mars and Venus: Comparing a one-dimensional photochemical model with MaRS (Mars Express) and VeRa (Venus Express) observations
González-Galindo, F.; Tellmann, Silvia; Tyler, G. Leonard +8 more
The electron density distributions of the lower ionospheres of Mars and Venus are mainly dependent on the solar X-ray and EUV flux and the solar zenith angle. The influence of an increasing solar flux is clearly seen in the increase of the observed peak electron density and total electron content (TEC) of the main ionospheric layers. The model “Io…