Search Publications
Columbia Hills, Mars: Aeolian features seen from the ground and orbit
Greeley, Ronald; Whelley, Patrick L.; Neakrase, Lynn D. V. +15 more
Abundant wind-related features occur along Spirit's traverse into the Columbia Hills over the basaltic plains of Gusev Crater. Most of the windblown sands are probably derived from weathering of rocks within the crater, and possibly from deposits associated with Ma'adim Vallis. Windblown particles act as agents of abrasion, forming ventifacts, and…
Tropospheric carbon monoxide concentrations and variability on Venus from Venus Express/VIRTIS-M observations
Drossart, Pierre; Irwin, Patrick G. J.; Piccioni, Giuseppe +7 more
We present nightside observations of tropospheric carbon monoxide in the southern hemisphere near the 35 km height level, the first from Venus Express/Visible and Infrared Thermal Imaging Spectrometer (VIRTIS)-M-IR. VIRTIS-M data from 2.18 to 2.50 µm, with a spectral resolution of 10 nm, were used in the analysis. Spectra were binned, with w…
Mineralogical composition, structure, morphology, and geological history of Aram Chaos crater fill on Mars derived from OMEGA Mars Express data
Le Mouélic, S.; Sotin, C.; Bibring, J. -P. +6 more
Aram Chaos is a crater 280 km in diameter centered at 2.5°N, 338.5°E. It is filled by chaotic terrains overlain by a dome-shaped, layered 900 m thick formation displaying spectral signatures of ferric oxides on Thermal Emission Spectrometer (TES) and Observatoire pour la Mineralogie, L'Eau, les Glaces et L'Activite (OMEGA) medium spatial resolutio…
Evidence for anomalous cloud particles at the poles of Venus
Carlson, R. W.; Irwin, P. G. J.; Drossart, P. +5 more
An analysis of near-infrared emissions on the nightside of Venus observed by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) instrument on board Venus Express reveals anomalous cloud particles in the polar regions of Venus. These anomalous particles are found within the centers of polar vortices at both poles and are either larger o…
Proton cyclotron waves in the solar wind at Venus
Zhang, T. L.; Volwerk, M.; Delva, M. +2 more
Magnetometer data from two Venus years of the Venus Express mission in orbit are investigated for the occurrence of ion cyclotron waves. Proton cyclotron waves were recently detected in the upstream region of Venus by the spacecraft, indicating pickup of planetary protons from Venus's exosphere by the solar wind and loss of hydrogen to interplanet…
Limb observations of the ultraviolet nitric oxide nightglow with SPICAV on board Venus Express
Bertaux, J. -L.; Villard, E.; Gérard, J. -C. +3 more
Limb observations of the spectrum of nightglow emission in the δ (190-240 nm) and γ (225-270 nm) bands of nitric oxide have been made with the Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus (SPICAV) ultraviolet spectrometer on board Venus Express. These emissions arise from radiative recombination between O(3
Gray hematite distribution and formation in Ophir and Candor chasmata
Weitz, Catherine M.; Lane, Melissa D.; Staid, Matthew +1 more
We have studied eight of the spatially largest locations in Ophir and Candor chasmata that have the highest abundances of coarse-grained gray hematite, as measured by the Mars Global Surveyor Thermal Emission Spectrometer (TES). All of the eight hematite locations correspond to relatively smooth dark units that overlie or are adjacent to light-ton…
Intermittent turbulence, noisy fluctuations, and wavy structures in the Venusian magnetosheath and wake
Zhang, T. L.; Baumjohann, W.; Volwerk, M. +3 more
Recent research has shown that distinct physical regions in the Venusian induced magnetosphere are recognizable from the variations of strength of the magnetic field and its wave/fluctuation activity. In this paper the statistical properties of magnetic fluctuations are investigated in the Venusian magnetosheath and wake regions. The main goal is …
Dielectric properties of the Martian south polar layered deposits: MARSIS data inversion using Bayesian inference and genetic algorithm
Nielsen, Erling; Zhang, Zhenfei; Plaut, Jeffrey J. +3 more
Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) has offered abundant data, which have been used to estimate dielectric properties of the south polar layered deposits (SPLD) of Mars. This paper presents a new way to invert the data to estimate the dielectric properties of the SPLD. A total of 4364 measurements were analyzed. The…
Retrieval of air temperature profiles in the Venusian mesosphere from VIRTIS-M data: Description and validation of algorithms
Irwin, P. G. J.; Drossart, P.; Piccioni, G. +7 more
We present here methods developed for the retrieval of air temperature profiles in the Venusian mesosphere from the absolute radiances measured by the Visual and Infrared Thermal Imaging Spectrometer (VIRTIS) on board the Venus Express satellite. The infrared M channel of the instrument acquires multispectral images between 1000 and 5000 nm. In ni…