In 2011, Sumi et al. announced the discovery of an excess of short-timescale microlensing events, which they inferred to be caused by a population of unbound planetary-mass objects. Their result implies that these free-floating planet candidates may constitute an overwhelming fraction of the mass budget for planet formation. K2's Campaign 9 (K2C9) will conduct a ~4 square-degree microlensing survey toward the Galactic bulge and is our first and potentially only opportunity to perform a synoptic survey to measure the masses of a substantial number of short-timescale events. The ∼0.5 AU baseline between K2 and the Earth during C9 will facilitate satellite parallax measurements for short-timescale events, with durations of ∼1 day, which will identify that the cause of the event is in fact a very low-mass object, i.e., a free-floating planet candidate. By taking near-infrared (NIR) photometry during the event and comparing to high-resolution NIR photometry after the event is over, we can then distinguish between a planet that is widely separated from but gravitationally bound to a host star and one that is truly free-floating. Here we overview this procedure, describe the resources available to accomplish it, and detail the expected yields.
American Astronomical Society Meeting Abstracts #227
- Pub Date:
- January 2016