An Extrasolar Planet Census with a Space-based Microlensing Survey.pdfVIP

1 An Extrasolar Planet Census with a Space-based Microlensing Survey D.P. Bennetta, J. Andersonb, J.-P. Beaulieuc, I. Bondd, E. Chenge, K. Cook f, S. Friedmang, B.S. Gaudih, A. Gouldh, J. Jenkinsi, R. Kimblej, D. Link, M. Richl, K. Sahu g, D. Tenerellim, A. Udalskin, and P. Yocko a University of Notre Dame, Notre Dame, IN, USA b Rice University, Houston, TX, USA c Institut d’Astrophysique, Paris, France d Massey University, Auckland, New Zealand e Conceptual Analytics, LLC, Glen Dale, MD, USA f Lawrence Livermore National Laboratory, USA g Space Telescope Science Institute, Baltimore, MD, USA h Ohio State University, Columbus, OH, USA i SETI Institute, Mountain View, CA, USA j NASA/Goddard Space Flight Center, Greenbelt, MD, USA k University of California, Santa Cruz, CA, USA l University of California, Los Angeles, CA, USA m Lockheed Martin Space Systems Co., Sunnyvale, CA, USA n Warsaw University, Warsaw, Poland o University of Auckland, Auckland, New Zealand 2 ABSTRACT A space-based gravitational microlensing exoplanet survey will provide a statistical census of exoplanets with masses 0.1M and orbital separations ranging from 0.5AU to . This includes analogs to all the Solar System’s planets except for Mercury, as well as most types of planets predicted by planet formation theories. Such a survey will provide results on the frequency of planets around all types of stars except those with short lifetimes. Close-in planets with separations 0.5 AU are invisible to a space-based microlensing survey, but these can be found by Kepler. Other methods, including ground-based microlensing, cannot approach the comprehensive statistics on the mass and semi-major axis distribution of extrasolar planets that a space-based microlensing survey will provide. The terrestrial planet sensitivity of a ground-based microlensing survey is limited to the vicinity of the Einstein radius at 2-3 AU, and space-based imaging is needed to identify and