[1] Univ Nantes, CNRS, F-44035 Nantes, France
[2] Univ London Imperial Coll Sci Technol & Med, London SW7 2AZ, England
[3] Univ Paris Diderot, UPMC Univ Paris 06, CNRS, LESIA Observ Paris, Paris, France
[4] Univ Leicester, Leicester LE1 7RH, Leics, England
[5] ESA ESTEC, Noordwijk, Netherlands
[6] IRAP Observ Midi Pyrenees, Toulouse, France
[7] UCL, London WC1E 6BT, England
[8] Univ Oxford, Clarendon Lab, Oxford OX1 3PU, England
[9] Inst Planetary Res, DLR, Berlin, Germany
[10] Max Planck Inst Sonnensyst Forsch, D-37191 Katlenburg Lindau, Germany
[11] CNRS Orleans, LPC2E, Orleans, France
[12] Ctr Astrobiol INTA CSIC, Madrid, Spain
[13] Univ Bologna, I-40126 Bologna, Italy
[14] Inst Space Astrophys & Planetol, Natl Inst Astrophys, Rome, Italy
[15] Roy Obs Belgium, Uccle, Belgium