Planet Masses in the Upsilon Andromadae system determined with the HST Fine Guidance Sensors

We report the masses of multiple planets in the Upsilon Andromadae system based upon Hubble Space Telescope Fine Guidance Sensor observations. We have performed a re-calibration of the Optical Field Distortion of the Fine Guidance Sensor 1, and implemented additional corrections and improvements in the calibration pipeline. We have used HST FGS measurements combined with radial velocity measurements from multiple sources, including high cadence measurements from the Hobby Eberly Telescope at McDonald Observatory to further explore the architecture of this extrasolar planetary system and better understand the formation and evolution of planetary systems. This work is supported by NASA through the Space Telescope Science Institute General Observer program; grants GO-09407, -09971, -10103, -10610, and -10989.