Spitzer as a Microlens Parallax Satellite: Mass Measurement for the OGLE-2014-BLG-0124L Planet and its Host Star

We combine Spitzer and ground-based observations to measure the microlens parallax vector pi(E), and thus the mass and distance of OGLE-2014-BLG-0124L, making it the first microlensing planetary system with a space-based parallax measurement. The planet and star have masses of m similar to 0.5M(jup) and M similar to 0.7M(circle dot) and are separated by a(perpendicular to) similar to 3.1AU in projection. The main source of uncertainty in all of these numbers (approximately 30%, 30%, and 20%) is the relatively poor measurement of the Einstein radius theta(E), rather than uncertainty in pE, which is measured with 2.5% precision. This compares to 22% based on OGLE data alone, implying that the Spitzer data provide not only a substantial improvement in the precision of the pE measurement, but also the first independent test of a ground-based pE measurement.