Affiliation: | a Department of Space Studies, Southwest Research Institute, 1050 Walnut Street, Suite 400, Boulder, CO 80302, USA b Institute for Astronomy, University of Hawaii, Honolulu, HI 96822-1897, USA c Observatoire de la Côte d'Azur, B.P. 4229, 06034 Nice Cedex 4, France d Institute of Astronomy, Charles University, V Holešovi?kách 2, 180 00 Prague 8, Czech Republic |