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-r adii eclipsing binary systems. Terrestrial planets in these systems should form in the binary orbital plane, and are likely to have periods significan tly smaller than those of the terrestrial planets in the Solar System, and hence, should be more easily detectable. Our observations of the CM Draconi s system indicate that such detections are indeed possible, especially when the photometric data (differential light curve) can be correlated with pos sible planetary orbital models of the quasi-periodic signal expected (i.e. a matched-filter implementation). The importance of the discovery of the fi rst habitable planets, and Follow-up observations for the detection of exob iology are outlined. In addition, non-transiting jovian-mass planets in suc h systems can also be detected by precisely timing the binary eclipse minim a. Our preliminary observations of ten such systems have demonstrated the f easibility of this detection method. Over two hundred such systems could be surveyed for jovian-mass planets, providing a statistically meaningful sam ple for understanding the formation of giant planets around close double st ars, thus complimenting our main objective: the detection of habitable-size d planets. (C) 2000 Elsevier Science Ltd. All rights reserved.