1. Center for Space and Habitability, University of Bern , Gesellschaftsstrasse 6, CH-3012 Bern, Switzerland
2. Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University , Box 43, 221 00 Lund, Sweden
3. Atmospheric, Oceanic & Planetary Physics, Department of Physics, University of Oxford , Oxford OX1 3PU, UK
4. University of Warwick, Department of Physics, Astronomy & Astrophysics Group , Coventry CV4 7AL, UK
5. Ludwig Maximilian University, University Observatory Munich , Scheinerstrasse 1, Munich D-81679, Germany