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Rheological and petrological implications for a stagnant lid regime on Venus
Ghail, Richard
Venus is physically similar to Earth but with no oceans and a hot dense atmosphere. Its near-random distribution of impact craters led to the inferences of episodic global resurfacing and a stagnant lid regime, and imply that it is not currently able to lose proportionately as much heat as Earth. This paper shows that a CO2-induced asth…
Preliminary study of Venus cloud layers with polarimetric data from SPICAV/VEx
Montmessin, Franck; Bertaux, Jean-Loup; Korablev, Oleg +4 more
We present unique polarization data from the SPICAV-IR spectrometer onboard ESA's Venus Express (VEx) spacecraft and a first retrieval of cloud parameters. The polarization data have been collected from 2006 to 2010, and cover mostly the northern hemisphere, in the 0.65 to 1.7 µm spectral range. They contain information about latitudinal and…
Water vapor near Venus cloud tops from VIRTIS-H/Venus express observations 2006-2011
Drossart, P.; Piccioni, G.; Ignatiev, N. I. +1 more
This work aims to give a summary of the water vapor at the cloud top of Venus atmosphere using the complete set of observations made using high spectral resolution channel (-H) of Visible and Infrared Thermal Imaging Spectrometer (VIRTIS), on board the ESA Venus Express orbiter, to measure the cloud top altitude and the water vapor abundance near …
Hydrogen halides measurements in the Venus mesosphere retrieved from SOIR on board Venus express
Vandaele, A. C.; Robert, S.; Wilquet, V. +5 more
The SOIR instrument on board Venus Express regularly sounds the Venus mesosphere using the solar occultation technique. Densities and volume mixing ratios of HCl and HF are measured in the 70-115 km and 75-110 km altitude region respectively, at the Venus terminator. All latitudes from pole to pole are covered. In this work, we study the latitude …
Optical properties of the Venus upper clouds from the data obtained by Venus Monitoring Camera on-board the Venus Express
Ignatiev, N. I.; Petrova, E. V.; Markiewicz, W. J. +2 more
During more than 6 years of the Venus Express (VEx) mission, the Venus Monitoring Camera (VMC) took around 300 000 images in four channels covering almost all the latitudes, including night and day sides. Here we give an overview of the VMC data and summarize results of retrievals of the optical properties of the Venus upper clouds. The in-flight …
Surface charging and electrostatic dust acceleration at the nucleus of comet 67P during periods of low activity
Coates, A. J.; Jones, G. H.; Roussos, E. +2 more
We have investigated through simulation the electrostatic charging of the nucleus of Comet 67P/Churyumov-Gerasimenko during periods of weak outgassing activity. Specifically, we have modeled the surface potential and electric field at the surface of the nucleus during the initial Rosetta rendezvous at 3.5 AU and the release of the Philae lander at…
Distribution of sulphuric acid aerosols in the clouds and upper haze of Venus using Venus Express VAST and VeRa temperature profiles
Vandaele, Ann Carine; Tellmann, Silvia; Pätzold, Martin +8 more
Observations from Pioneer Venus and from SPICAV/SOIR aboard Venus Express (VEx) have shown the upper haze (UH) of Venus to be highly spatially and temporally variable, and populated by multiple particle size modes. Previous models of this system (e.g., Gao et al., 2014. Icarus 231, 83-98), using a typical temperature profile representative of the …
Late Noachian fluvial erosion on Mars: Cumulative water volumes required to carve the valley networks and grain size of bed-sediment
Rosenberg, Eliott N.; Head, James W., III
Our goal is to quantify the cumulative water volume that was required to carve the Late Noachian valley networks on Mars. We employ an improved methodology in which fluid/sediment flux ratios are based on empirical data, not assumed. We use a large quantity of data from terrestrial rivers to assess the variability of actual fluid/sediment flux sed…
The VMC/VEx photometry at small phase angles: Glory and the physical properties of particles in the upper cloud layer of Venus
Markiewicz, Wojciech J.; Petrova, Elena V.; Shalygina, Oksana S.
With the Venus Monitoring Camera onboard the Venus Express orbiter, for the first time full glory on the upper cloud layer of Venus has been imaged. Images were acquired in three wavelengths of 0.365, 0.513, and 0.965 µm. Glory is an optical phenomenon that poses stringent constraints on the cloud properties. The fact of the observed glory i…
Upper atmosphere temperature structure at the Venusian terminators: A comparison of SOIR and VTGCM results
Wilquet, V.; Mahieux, A.; Brecht, A. S. +5 more
Venus Express SOIR terminator profiles of CO2 densities and corresponding temperatures have been determined for 132 selected orbits obtained between 2006 and 2013. These recently recalibrated measurements provide temperature profiles at the Venusian terminator over approximately 70-160 km, revealing a striking permanent temperature mini…