1. Department of Earth, Atmospheric & Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
2. Department of Physics and Astronomy, Center for Interdisciplinary Exploration and Research in Astrophysics, Northwestern University, Evanston, Illinois, USA.
3. Blue Marble Space Institute of Science, Seattle, Washington, USA.
4. Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, USA.
5. Department of Earth and Space Sciences, University of Washington, Seattle, Washington, USA.
6. Harvard College, Cambridge, Massachusetts, USA.