1. Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
2. Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany
3. Astrophysikalisches Institut und Universitätssternwarte, Friedrich-Schiller-Universität Jena, Schillergäßchen 2-3, D-07745 Jena, Germany
4. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove drive, Pasadena, CA 91109, USA
5. Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
6. Centre for Exoplanets and Habitability, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
7. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA