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B. L. Lee (University of Toronto)
We present results from the EXPLORE/OC survey for transiting close-in extrasolar giant planets in open clusters. Each observed cluster of coeval stars at a common distance allows us to sample G, K, and M-dwarfs at a specific stellar metallicity and age. Hence, we seek to investigate the occurrence and properties of planets and variable stars as a function of stellar parameters, in environments with constrained chemical, dynamical, and evolutionary histories.
Our survey of eight southern open clusters, with a range of ages and metallicities, is presently the largest open cluster transit search data set obtained with a uniform technique. Over all eight open clusters, we have surveyed about 40000 stars to relative photometric precisions of 2-15 millimag.
We achieve our excellent photometric precision in our light curves using a new high-precision photometry pipeline incorporating neighbour subtraction and a generalized aperture technique. Our data mining combines multiple automated variable finding techniques, with verification by eye. We report on the effectiveness of these methods in searching for planet transit candidates and variable stars.
We show light curves, estimate spectral types, and consider cluster membership probability of planet transit candidates. We discuss the likelihood that these candidates are planets. Also, based on the tens of other variable light curves discovered per cluster, we compute binary and variable star fractions for our clusters, and examine the statistics as a function of cluster age and metallicity, to probe the evolution and properties of binary and variable star populations.
The author(s) of this abstract have provided an email address for comments about the abstract: blee@astro.utoronto.ca
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.