HR: 08:30h
AN: P41B-03    [Abstracts]
TI: The Venus Express VIRTIS and MESSENGER teams
AU: * Helbert, J
EM: joern.helbert@dlr.de
AF: Institute for Planetary Research DLR, Rutherfordstrasse 2, Berlin, 12489, Germany
AU: Robinson, M S
EM: mrobinson@asu.edu
AF: School of Earth and Space Exploration, Box 871404, Tempe, AZ 85287-1404, United States
AU: Muller, N
EM: nils.mueller@dlr.de
AF: Institute for Planetary Research DLR, Rutherfordstrasse 2, Berlin, 12489, Germany
AU: Prockter, L M
EM: louise.prockter@jhuapl.edu
AF: The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, United States
AU: Head, J W
EM: james_head_III@brown.edu
AF: Department of Geological Sciences, Brown University, Providence, RI 02912, United States
AU: Izenberg, N R
EM: noam.izenberg@jhuapl.edu
AF: Department of Geological Sciences, Brown University, Providence, RI 02912, United States
AU: Solomon, S C
EM: scs@dtm.ciw.edu
AF: Department of Terrestrial Magnetism Carnegie Institution of Washington, 5241 Broad Branch Road, N.W, Washington, DC 20015, United States
AU: Svedhem, H
EM: hsvedhem@esa.int
AF: ESA, Keplerlaan 1, Noordwijk, 2200, Netherlands
AU: Piccioni, G
EM: giuseppe.piccioni@iasf-roma.inaf.it
AF: INAF - IASF Roma, Via del Fosso del Cavaliere 100, Roma, 00133, Italy
AU: Drossart, P
EM: pierre.drossart@obspm.fr
AF: LESIA - Observatoire de Paris, 61 avenue de l'observatoire, Paris, 75014, France
AU: MESSENGER team, T a
AB: Because Venus Express has been in orbit around Venus since April 2006, MESSENGER's flyby of Venus on 5 June 2007 permitted a coordinated campaign of two-spacecraft observations of that planet. Here we report initial results from joint observations of the surface of Aphrodite Terra performed by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on Venus Express and the Mercury Dual Imaging System (MDIS) on MESSENGER. VIRTIS observed the region 13 hours before and 9 hours after the time of MESSENGER's closest approach (when Venus Express was on the opposite side of the planet). This timeline of nearly 24 hours allows the disentangling of variable atmospheric conditions from surface signals. Both instruments were able to observe the surface in the 1.02 μ m atmospheric window. At this wavelength the CO₂ atmosphere allows about 95% of the thermal radiation from the surface to escape. In addition VIRTIS could make observations in the atmospheric windows at 1.10 and 1.18 μ m, which are less transparent. Radiative transfer models were used to invert VIRTIS images at 1.02, 1.10, and 1.18 μ m for the thermal emission of the surface. Local atmospheric transmittance is derived from VIRTIS images at 1.31 μ m. The combined MDIS and VIRTIS data set covers almost the entire extent of southern Aphrodite Terra. Both instruments observed as expected a correlation between topography and thermal radiation, as the surface temperature on Venus is dominantly a function of altitude. There are, however, tentative indications of possible surface emissivity differences between highland material and the adjacent lowlands. Detailed data analysis and interpretation within the framework of the geology of the region are currently underway.
DE: 5464 Remote sensing
DE: 5470 Surface materials and properties
DE: 5480 Volcanism (6063, 8148, 8450)
DE: 6295 Venus
DE: 6297 Instruments and techniques
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting