Assigned ID: 218 ----- Submission 1 (Fri Jan 21 16:21:31 GMT 2005) ----- ----- Submission 3 (Sun Jan 23 02:08:01 GMT 2005) ----- We propose observations with HST/FGS to estimate the astrometric elements (perturbation orbit semi-major axis and inclination) of extra-solar planets orbiting six stars. These companions were originally detected by radial velocity techniques. We have demonstrated that FGS astrometry of even a short segment of reflex motion, when combined with extensive radial velocity information, can yield useful inclination information (McArthur et al. 2004), allowing us to determine companion masses. Extrasolar planet masses assist in two ongoing research frontiers. First, they provide useful boundary conditions for models of planetary formation and evolution of planetary systems. Second, knowing that a star in fact has a plantary mass companion, increases the value of that system to future extrasolar planet observation missions such as SIM PlanetQuest, TPF, and GAIA.

COOL STARS 12 false 0.0 false false false false true SUPPORTED 06 37 47.6189 -32 20 23.04 J2000 15 18 55.4719 -01 35 32.59 J2000 18 20 3.9316 -09 35 44.60 J2000 16 10 24.3143 +43 49 3.52 J2000 05 46 34.9120 +01 10 5.50 J2000 05 11 46.4490 +04 24 12.74 J2000 FGS POS No F5ND FGS POS No F5ND FGS POS No F5ND FGS POS No F5ND FGS POS No F5ND FGS POS No F5ND false -1 -1