GROUND-BASED DETECTABILITY OF TERRESTRIAL AND JOVIAN EXTRASOLAR PLANETS - OBSERVATIONS OF CM DRACONIS AT LICK OBSERVATORY

The detection of terrestrial-sized extrasolar planets from the ground has been thought to be virtually impossible due to atmospheric scintil lation limits. However, we show that this is not the case for speciall y selected (but nevertheless main sequence) stars, namely small eclips ing binaries. For the smallest of these systems, CM Draconis, several months to a few years of photometric observations with 1-m-class teles copes will be sufficient to detect the transits of any short-period pl anets of sizes greater than or equal to 1.5 Earth radii (R(E)), using cross-correlation analysis with moderately good photometry. Somewhat l arger telescopes will be needed to extend this detectability to terres trial planets in larger eclipsing binary systems. (We arbitrarily defi ne ''terrestrial planets'' herein as those whose disc areas are closer to that of Earth's than Neptune's i.e., less than about 2.78 R(E).) A s a ''spin-off' of such observations, we will also be able to detect t he presence of Jovian-mass planets without transits using the timing o f the eclipse minima. Eclipse minima will drift in time as the binary system is offset by a sufficiently massive planet (i.e., one Jupiter m ass) about the binary/giant-planet barycenter, causing a periodic vari ation in the light travel time to the observer. We present here an out line of present observations taking place at the University of Califor nia Lick Observatory using the Crossley 0.9-m telescope in collaborati on with other observatories (in South Korea, Crete, France, Canary Isl ands, and New York) to detect or constrain the existence of terrestria l planets around main sequence eclipsing binary star systems, starting with CM Draconis. We demonstrate the applicability of photometric dat a to the general detection of gas giant planets via eclipse minima tim ings in many other small-mass eclipsing binary systems as well.