AAS 195th Meeting, January 2000
Session 24. Extrasolar Planets and Substellar Companions
Oral, Wednesday, January 12, 2000, 10:00-11:30am, Regency VI

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[24.01] The Vulcan Photometer: A Dedicated Photometer for Extrasolar Planet Searches

W. J. Borucki, D. A. Caldwell, D. G. Koch (NASA Ames Research Center), L. D. Webster, J. M. Jenkins (SETI Institute), Z. Ninkov (Rochester Institute of Technology)

A small CCD photometer dedicated to the detection of extrasolar planets has been developed and put into operation at Mt. Hamilton, California. It simultaneously monitors 6000 stars brighter than 13th magnitude in its 49 square-degree field of view. Observations are conducted all night every clear night of the year. A single field is monitored at a cadence of eight images per hour for a period of about three months. When the data are folded and phased for the purpose of discovering low amplitude transits, transit amplitudes of 1% are readily detected This precision is sufficient to find jovian-size planets orbiting solar-like stars, which have signal amplitudes from 1% to 2% depending on the inflation of the planet's atmosphere and the size of the star.

Over one hundred variable stars have been found in each star field. About fifty of these stars are eclipsing binary stars, several with transit amplitudes of only a few percent. Three stars that showed only primary transits were examined with high-precision spectroscopy. Two were found to be nearly identical stars in binary pairs orbiting at double the photometric period. Spectroscopic observations showed the third star to be a high mass-ratio single-lined binary. The Vulcan observations show that the photometer has the necessary relative precision to find companions with the expected area ratio for jovian-size planets orbiting solar-like stars.

The author(s) of this abstract have provided an email address for comments about the abstract: wborucki@mail.arc.nasa.gov

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