[1] Laboratoire d'Astrophysique de Marseille, UMR 6110, Université de Provence, Traverse du Siphon, 13376 Marseille, France
[2] LESIA, CNRS UMR 8109, Observatoire de Paris, 5 place J. Janssen, 92195 Meudon, France
[3] IAS, Université Paris XI, 91405 Orsay, France
[4] Instituto de Astrofísica de Canarias, 38205 La Laguna, Spain
[5] School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL, United Kingdom
[6] Physikalisches Institut, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
[7] Institut d'Astrophysique de Paris, UMR7095 CNRS, Université Pierre and Marie Curie, 98bis Bd Arago, 75014 Paris, France
[8] Observatório Nacional, Rio de Janeiro, RJ, Brazil
[9] Institute for Astronomy, University of Vienna, Türkenschanzstrasse 17, 1180 Vienna, Austria
[10] Institute of Planetary Research, DLR, Rutherfordstr. 2, 12489 Berlin, Germany
[11] Research and Scientific Support Department, European Space Agency, ESTEC, 2200 Noordwijk, Netherlands
[12] Observatoire de Genève, Université de Genève, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland
[13] Observatoire de la Côte d'Azur, Laboratoire Cassiopée, CNRS UMR 6202, BP 4229, 06304 Nice Cedex 4, France
[14] Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany
[15] Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, 8042 Graz, Austria
[16] Institut d'Astrophysique et de Géophysique, Université de Liège, Allée du 6 août 17, Sart Tilman, Liège 1, Belgium
[17] School of Physics and Astronomy, R. and B. Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978, Israel
[18] Rheinisches Institut für Umweltforschung, Universität zu Köln, Abt. Planetenforschung, Aachener Str. 209, 50931 Köln, Germany
[19] Center for Astronomy and Astrophysics, TU Berlin, Hardenbergstr. 36, 10623 Berlin, Germany
[20] LUTH, Observatoire de Paris-Meudon, 5 place J. Janssen, 92195 Meudon, France