Presentation #218.03 in the session “Exoplanet Populations: Masses and Microlensing”.
I present Keck adaptive optics (AO) observations of the microlensing target OGLE-2011-BLG-0950, which enable the lens to be directly detected. The initial analysis of Choi et al. (2013) resulted in two degenerate solutions. The authors conclude that the host(lens) star has either a Jupiter-mass planet or a stellar-mass companion orbiting it. One problem that plagues the interpretation of some microlensing events is the existence of degenerate solutions that can explain the light curve with very different physical parameters. I present a new method to resolve such degeneracies. The lens detection and mass measurement analysis described in this work represents an essential building block for the upcoming Nancy Grace Roman Space Telescope. The Roman microlensing mission will use this same technique to measure the masses for a large fraction of the exoplanets that it will discover.