Results from a photometric search for extrasolar planetary transits across the eclipsing binary CM Dra are presented .
The TEP ( Transits of Extrasolar Planets ) network has observed this star since 1994 , and a lightcurve with 617 hours of coverage has been obtained .
The data give a complete phase coverage of the CM Dra system at each of the 3 years of observations , with a noise of less than 5 mmag .
New epoch and period values for CM Dra are derived , and a low flare rate of 0.025 hr ^ { -1 } has been confirmed .
The absence of periodic variations in eclipse minimum times excludes the presence of very massive planets with periods of less than a few years .
The lightcurve was visually scanned for the presence of unusual events which may be indicative of transits of extrasolar planets with ’ massive earth ’ sizes .
Six suspicious events were found which are being followed up for future transits , by planets with sizes between 1.5 and 2.5 R _ { E } ( Earth Radii ) .
However , none of these events has amplitudes compatible with planets larger than 2.5 R _ { E } .
Coplanar planets larger than 2.5 R _ { E } and with orbital periods of less than 60 days can therefore be ruled out with a confidence of about 80 % .
Planets smaller than 1.5 R _ { E } can not be detected in the data without a sub-noise detection algorithm .
A preliminary signal detection analysis shows that there is a 50 % detection confidence for 2 R _ { E } planets with a period from 10 to 30 days with the current data .
This data-set demonstrates that it is possible to detect terrestrial sized planets with ground based photometry , and that strong constraints on the sizes of planets orbiting in the plane of the CM Dra system can be set .