Searching for planetary transits in the field of open cluster NGC 6819 - I

We present results from our survey for planetary transits in the field of the intermediate-age (~2.5 Gyr), metal-rich ([Fe/H] ~ +0.07) open cluster NGC 6819. We have obtained high-precision time-series photometry for over 38 000 stars in this field and have developed an effective matched-filter algorithm to search for photometric transits. This algorithm identified 8 candidate stars showing multiple transit-like events, plus 3 stars with single eclipses. On closer inspection, while most are shown to be low-mass stellar binaries, some of these events could be the result of brown dwarf companions. The data for one of the single-transit candidates indicate a minimum radius for the companion similar to that of HD 209458b.