Ground-based photometric detection of extrasolar planets

The discovery of terrestrial-sized extrasolar planets around main-sequences stars is currently possible from the ground for several sub-solar, small-radii eclipsing binary systems. Terrestrial planets in these systems should form in the binary orbital plane, and are likely to have periods significantly smaller than those of the terrestrial planets in the Solar System, and hence, should be more easily detectable. Our observations of the CM Draconis system indicate that such detections are indeed possible, especially when the photometric data (differential light curve) can be correlated with possible planetary orbital models of the quasi-periodic signal expected (i.e. a matched-filter implementation). The importance of the discovery of the first habitable planets, and Follow-up observations for the detection of exobiology are outlined. In addition, non-transiting jovian-mass planets in such systems can also be detected by precisely timing the binary eclipse minima. Our preliminary observations of ten such systems have demonstrated the feasibility of this detection method. Over two hundred such systems could be surveyed for jovian-mass planets, providing a statistically meaningful sample for understanding the formation of giant planets around close double stars, thus complimenting our main objective: the detection of habitable-sized planets. (C) 2000 Elsevier Science Ltd. All rights reserved.