P21A-2055
Study of the Martian cold oxygen corona from the O I 130.4 nm by IUVS/MAVEN
Tuesday, 15 December 2015
Poster Hall (Moscone South)
Jean-Yves Chaufray1, Justin Deighan2, Michael Chaffin2, Nicholas McCord Schneider3, Bill McClintock2, Ian F Stewart2, Sonal Jain2, Matteo Michael James Crismani2, Arnaud Stiepen3, Greg Holsclaw2, John T Clarke4, Franck Montmessin1, Francis Gerard Eparvier3, Ed Thiemann2, Phillip C Chamberlin5 and Bruce Martin Jakosky2, (1)LATMOS Laboratoire Atmosphères, Milieux, Observations Spatiales, Paris Cedex 05, France, (2)Laboratory for Atmospheric and Space Physics, Boulder, CO, United States, (3)University of Colorado at Boulder, Boulder, CO, United States, (4)Boston University, Boston, MA, United States, (5)NASA Goddard Space Flight Center, Greenbelt, MD, United States
Abstract:
The observations of the O I 130.4 nm resonant line performed by the Imaging Ultraviolet Spectrograph (IUVS) aboard the Mars Atmosphere and Volatile Evolution Mission (MAVEN) are presented. This emission line is observed during the different orbit phases of MAVEN : disk observations at apoapsis, limb scans at periapsis and coronal scans during the outbound orbit leg. The atomic oxygen density which is an important parameter to understand the heating, composition, dynamics of the Martian upper atmosphere and the temperature at 200 km are retrieved from an automatic inversion algorithm. A set of observations performed by IUVS during the first months of the mission are analyzed to study the variabiity of the atomic oxygen in the Martian upper atmosphere. The derived oxygen density and the temperature at the exobase are in the predicted range (107 - 108 cm-3; 200 – 300K) by the current thermospheric models of Mars. The derived parameters are very sensitive to the absolute calibration of the instrument which is the main source of uncertainty on the results presented.
