1. Faculdade de Engenharia, Universidade do Porto, rua Dr Roberto Frias, P-4200-465 Porto, Portugal
2. CENTRA – Centro de Astrofísica e Gravitação, IST, Universidade de Lisboa, P-1049-001 Lisboa, Portugal
3. School of Physics, Astrophysics Group, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
4. Universidade de Lisboa – Faculdade de Ciências, Campo Grande, P-1749-016 Lisboa, Portugal
5. Max Planck Institute for Extraterrestrial Physics, Giessenbachstr, D-85748 Garching, Germany
6. Observatoire de Paris Meudon, F-92195 Meudon Cedex, Paris, France
7. Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg, Germany
8. 1 Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany
9. Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Grenoble, France