<title>CCD photometry tests for a mission to detect Earth-sized planets in the extended solar neighborhood</title>

Abstract

The thirty or so extrasolar planets that have been discovered to date are all about as large as Jupiter or larger. Finding Earth-size planets is a substantially more difficult task. We propose the use of spacebased differential photometry to detect the periodic changes in brightness of several hours duration caused by planets transiting their parent stars. The change in brightness for a Sun-Earth analog transit is 8 X 10<SUP>-5</SUP>. We describe the instrument and mission concepts that will monitor 100,000 main-sequence stars and detect on the order of 500 Earth-size planets, if terrestrial planets are common in the extended solar neighborhood.