1. School of Physics and Astronomy, University of Birmingham , Edgbaston, Birmingham B15 2TT, UK
2. Stellar Astrophysics Centre (SAC), Department of Physics and Astronomy, Aarhus University , Ny Munkegade 120, DK-8000 Aarhus C, Denmark
3. Center for Space Science, NYUAD Institute, New York University Abu Dhabi , PO Box 129188, Abu Dhabi, United Arab Emirates