1. Centre for Exoplanets and Habitability, University of Warwick, Coventry CV4 7AL, UK
2. Department of Physics, University of Warwick, Coventry CV4 7AL, UK
3. European Southern Observatory, Karl-Schwarzschild-Straße 2, D-85748 Garching, Germany
4. Departament de Física, Universitat Politécnica de Catalunya, c/Esteve Terrades 5, E-08860 Castelldefels, Spain