[1] Harvard Univ, Dept Earth & Planetary Sci, Cambridge, MA 02138 USA
[2] Univ British Columbia, Dept Earth Ocean & Atmospher Sci, Vancouver, BC, Canada
[3] Planetary Sci Inst, Tucson, AZ USA
[4] CALTECH, Jet Prop Lab, Pasadena, CA USA
[5] NASA Goddard Space Flight Ctr, Greenbelt, MD USA
[6] La Mans Univ, Univ Angers, Nantes Univ, CNRS,LPG UMR, F-6112 Nantes, France
[7] Univ Calif Berkeley, Space Sci Lab, Berkeley, CA USA
[8] CNRS, IRAP, Toulouse, France