1. Universität Bonn, Argelander-Institut für Astronomie , Auf dem Hügel 71, D-53121 Bonn , Germany
2. Department of Astronomy, Oskar Klein Centre, Stockholm University , AlbaNova University Centre, SE-106 91 Stockholm , Sweden
3. Department of Astronomy and Theoretical Physics, Lund Observatory, Lund University , Box 43, SE-221 00 Lund , Sweden
4. European Southern Observatory , Karl-Schwarzschild-Straße 2, D-85748 Garching , Germany
5. Department of Physics & Astronomy, Macalester College , 1600 Grand Avenue, Saint Paul, MN 55105 , USA
6. European Southern Observatory , Av. Alonso de Córdova 3107, 763 0355 Vitacura, Santiago , Chile