The results of detailed simulations of space and ground based microlensing searches for extra-solar terrestrial planets are presented. These simulations indicate that the proposed Galactic Exoplanet Survey Telescope (GEST) can perform a comprehensive survey of extra-solar planetary systems with sensitivity to planets with masses as low as that of Mars (0.1M⊕ ) in orbits ranging from ∼ 0.7AU to infinity. In contrast, a multi-site ground based survey telescopes similar to VISTA or individual PAN-Stars telescopes, would be unlikely to discover a single Earth-like planet due the inability to resolve Galactic bulge main sequence stars from the ground, and the difficulty of obtaining 24 hour light curve coverage with good observing conditions. A space-based microlensing survey like GEST will be able to measure the abundance of extra-solar planets as a function of planet:star mass ratio and separation. For one third of detected events, the lens star will be detected, and this will allow the determination of the stellar type, mass and distance of the planetary host stars. A space-based microlensing survey is the only proposed method which can measure the abundance of free-floating planets which have been ejected from their parent stars. GEST can be accomplished at low risk with established technology at a cost that is within the cost cap of NASA's Discovery Program, but the prospects for planet detection from a possible future network large wide-field of view telescopes is unlikely to justify the funds necessary to build such s telescope network.
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 2003