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VIRTIS emissivity of Alpha Regio, Venus, with implications for tessera composition
Gilmore, Martha S.; Helbert, Jörn; Mueller, Nils
The composition of Venus tessera terrain is unknown. The Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) aboard Venus Express (VEx) collects data that yields the surface emissivity at ∼1 µm, which contains information convolving a number of surface properties, including composition. We examine the variation of emissivity in the vi…
Thermal evolution of Venus with argon degassing
O'Rourke, Joseph G.; Korenaga, Jun
Decades-old measurements of atmospheric and elemental surface composition constrain the history of Venus. In this study, we search for a model featuring continuous evolution in the stagnant-lid regime that predicts the present-day atmospheric mass of radiogenic argon and satisfies the other available constraints. For comparison, we also consider t…
Lithospheric structure of Venus from gravity and topography
Ruiz, Javier; Jiménez-Díaz, Alberto; Kirby, Jon F. +3 more
There are many fundamental and unanswered questions on the structure and evolution of the venusian lithosphere, which are key issues for understanding Venus in the context of the origin and evolution of the terrestrial planets. Here we investigate the lithospheric structure of Venus by calculating its crustal and effective elastic thicknesses (T
Vertical profiles of H2O, H2SO4, and sulfuric acid concentration at 45-75 km on Venus
Krasnopolsky, Vladimir A.
A method developed by Krasnopolsky and Pollack (Krasnopolsky, V.A., Pollack, J.B. [1994]. Icarus 109, 58-78) to model vertical profiles of H2O and H2SO4 vapors and sulfuric acid concentration in the Venus cloud layer has been updated with improved thermodynamic parameters for H2O and H2SO…
Constraints on a potential aerial biosphere on Venus: I. Cosmic rays
Coates, Andrew J.; Jones, Geraint H.; Patel, Manish R. +3 more
While the present-day surface of Venus is certainly incompatible with terrestrial biology, the planet may have possessed oceans in the past and provided conditions suitable for the origin of life. Venusian life may persist today high in the atmosphere where the temperature and pH regime is tolerable to terrestrial extremophile microbes: an aerial …
Coordinated Hubble Space Telescope and Venus Express Observations of Venus' upper cloud deck
Bertaux, Jean-Loup; Marcq, Emmanuel; Wilson, Colin +10 more
Hubble Space Telescope Imaging Spectrograph (HST/STIS) UV observations of Venus' upper cloud tops were obtained between 20N and 40S latitude on December 28, 2010; January 22, 2011 and January 27, 2011 in coordination with the Venus Express (VEx) mission. The high spectral (0.27 nm) and spatial (40-60 km/pixel) resolution HST/STIS data provide the …
Long-term variations of the UV contrast on Venus observed by the Venus Monitoring Camera on board Venus Express
Schröder, S. E.; Imamura, T.; Marcq, E. +1 more
We analyze the Venus ultraviolet (UV) reflectivity as observed by the Venus Monitoring Camera on board Venus Express over 2000 orbits in the years 2006-2011. We compare several laws for the photometric correction of global images of Venus, and find that the combined law of Lambert and Lommel-Seeliger is most suitable for our study. Our analysis of…
Ionization of the venusian atmosphere from solar and galactic cosmic rays
Coates, A. J.; Jones, G. H.; Desorgher, L. +2 more
The atmospheres of the terrestrial planets are exposed to solar and galactic cosmic rays, the most energetic of which are capable of affecting deep atmospheric layers through extensive nuclear and electromagnetic particle cascades. In the venusian atmosphere, cosmic rays are expected to be the dominant ionization source below ∼100 km altitude. Whi…
Vertical propagation of planetary-scale waves in variable background winds in the upper cloud region of Venus
Futaana, Yoshifumi; Imamura, Takeshi; Kouyama, Toru +2 more
Recently it was found that the low-latitude zonal wind and the amplitudes of Kelvin and Rossby waves at the cloud top of Venus show long-term variations in a synchronized manner. For the purpose of explaining this synchronization, we investigated the influence of the background zonal wind profile on the upward propagation of Kelvin and Rossby wave…
Carbon monoxide and temperature in the upper atmosphere of Venus from VIRTIS/Venus Express non-LTE limb measurements
López-Valverde, M. A.; Gilli, G.; Drossart, P. +4 more
The upper mesosphere and the lower thermosphere of Venus (from 90 to 150 km altitude) seems to play a transition region in photochemistry, dynamics and radiation, but is still very poorly constrained observationally. Since 2006 VIRTIS on board Venus Express has been obtaining limb observations of CO fluorescent infrared emissions in a systematic m…