[1] Univ Paris 06, LESIA Observ Paris, CNRS, F-92195 Meudon, France
[2] Kharkov Natl Univ, Inst Astron, UA-61022 Kharkov, Ukraine
[3] Univ Paris Diderot, F-75205 Paris, France
[4] Ithaca Coll, Dept Phys, Ithaca, NY 14850 USA
[5] Ist Fis Spazio InterplanetarioINAF, Rome, Italy
[6] Ist Astrofis Spaziale & Fis Cosm INAF, Rome, Italy
[7] Osservatorio Astron Roma INAF, Rome, Italy
[8] Observ Paris, IMCCE, F-75014 Paris, France
[9] Max Planck Inst Sonnensyst Forsch, D-37191 Katlenburg Lindau, Germany
[10] Univ Bern, Inst Phys, CH-3012 Bern, Switzerland