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T. M. Brown (HAO), D. Charbonneau (HAO; CfA)
Radial velocity surveys of nearby, solar-type stars have revealed nine planets that orbit their parent stars with a separation of a \lesssim 0.1 A.U. Close-in, extrasolar giant planets such as these will produce a measurable photometric dimming of the star as the planet transits the stellar disk. The motivation to undertake a transit search is strong: It may be the first detection of extrasolar planets by a method other than the radial velocity technique. Furthermore, it would be the first survey of planets that is not strongly biased toward solar-type stars. In combination with follow-up radial velocity observations, transit measurements will yield a direct measurement of the planetary radius and mass, which can be combined to calculate the average density and surface gravity. These would provide the first measurements of the physical characteristics of the planet, and provide the first constraints on the structural models.
The STARE instrument is a small aperture (10 cm), wide-field (6 degree square), CCD-based telescope that delivers high cadence (2 minute) time series photometry on roughly 40,000 stars (9 < V < 14) in a typical field centered on the galactic plane. In a typical two-month observing run on a single field, sufficient precision is obtained on roughly 4,000 stars to detect a close-in Jupiter-sized companion in a near edge-on orbit. The project is now in its third season, and has acquired a large dataset on several fields. Based on the results of the radial velocity projects, roughly one star in 1,500 surveyed should show transits due to a hot Jupiter. Thus, the STARE project should either detect numerous Jupiter-sized planets, or, in the event of a non-detection, establish that the radial velocity signatures are not due to large-radius, planetary-mass orbital companions.
The STARE project is funded by the NASA Origins of Solar Systems program.
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The author(s) of this abstract have provided an email address for comments about the abstract: timbrown@hao.ucar.edu