Discovery of a Low-mass Planet Orbiting a Low-mass Star in Microlensing Event MOA-2007-BLG-192

We present the analysis of microlensing event MOA-2007-BLG-192, which is the first microlensing planet discovery without the benefit of follow-up observations. The light curve reveals both the microlensing parallax effect and finite source effects, which imply that both the planet and its host must have low masses. However, the light curve coverage is somewhat sparse, so these mass estimates are not yet precise. High resolution adaptive optics images with the VLT/NACO instrument confirm the conclusion from the light curve that the host star must be very faint, and future observations with HST should determine the properties of the planet and its host star more precisely.

This work was funded in part by NASA and the NSF.