Discovering planets using Campaign 9 microlensing data

[christinahedges]

Microlensing surveys offer a way to detect planets at very large separations from their host stars, exploring an area of parameter space that is difficult to achieve with either the transit method or the radial velocity method (e.g. Penny et al. 2018). During K2 Campaign 9, Kepler monitored an area of 3.7 square degrees towards the Galactic Bulge (Henderson et al. 2016). During this 70-day Campaign, several dozen exoplanet microlensing events are known9 to have been observed simultaneously from space and from the ground (e.g. Zhu et al. 2017; Kim et al. 2018). The resulting parallax measurements should in principle allow for the direct measurement of the masses of and distances to the lensing systems, thereby resolving degeneracies. To date this dataset has not been used to detect transiting planets. The K2 Campaign 9 data is challenging in nature owing to the data formats, the motion systematics, and the crowding (e.g. see Poleski et al. 2018). We also note that the C9 data set can be used to reveal variables of all types towards the Galactic Bulge, including distance markers such as RR Lyrae stars.