Present and NearFuture Reflected Light Searches for CloseIn Planets.pdf

Disks, Planetesimals, and Planets ASP Conference Series, Vol. ***, 2000 F. Garz´on and T. J. Mahoney, eds. Present and Near-Future Reflected Light Searches for Close-In Planets David Charbonneau1,2 and Robert W. Noyes1 1Harvard-Smithsonian Center for Astrophysics, 60 Garden St., 0 0 Cambridge, MA 02138, USA 0 2 2 High Altitude Observatory, National Center for Atmospheric Research, P. O. Box 3000, Boulder, C0 80307, USA b e F Abstract. Close-in extrasolar giant planets may be directly detectable 6 by their reflected light, due to the proximity of the planet to the illu- 2 minating star. The spectrum of the system will contain a reflected light component that varies in amplitude and Doppler shift as the planet orbits 1 the star. Intensive searches for this effect have been carried out for only v 9 one extrasolar planet system, τ Bo¨o. There exist several other attractive 8 targets, including the transiting planet system HD 209458. 4 2 0 0 0 1. Introduction and Motivation / h Radial velocity surveys of nearby Sun-like stars have uncovered a population of p - close-in orbiting companions of roughly Jupiter mass. The ten such objects with o semi-major axes a 0.1 AU are listed in Table 1, along with the values for the r ∼ t semi-major axes, (minimum) masses, spectral types of the stars, and equilibrium s a temperatures (calculated from the estimated values for th