Paper: astro-ph/0505281
Date: Fri, 13 May 2005 12:04:38 GMT (94kb)
Title: Search for Planetary Candidates within the OGLE Stars
Authors: Adriana V. R. Silva and Patricia C. Cruz
Comments: 5 figures
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We propose a method to distinguish between planetary and stellar companions
to stars which present a periodic decrease in brightness, interpreted as a
transit. Lightcurves from a total of 133 stars from the OGLE project were
fitted by the model which simulates planetary transits using an opaque disk in
front of a white-light image of the Sun. The simulation results yield the
orbital radius (adopting circular orbit) in units of stellar radii, the orbit
inclination angle, and the ratio of the planet to the star radii, taking as
input the orbital period provided by the OGLE data. Using a mass-radius
relation for main sequence stars, it was possible to estimate values for
stellar mass and radius, and therefore absolute values for the companion and
the
orbit radii. This model was sucessfully tested with the stars HD 209458,
OGLE-TR-10, 56, 111, 113, and 132. The method consists of selecting as
planetary candidates only those objects with primary masses less than 2 solar
masses, representative of the OGLE solar type stars, and secondaries with
radius less than 1.5 Jupiter radius. We propose a selection of 20 planetary
candidates (OGLE-TR-49, 51, 55, 63, 71, 73, 76, 78, 82, 90, 97, 100, 109, 114,
126, 127, 129, 130, 131, and 134) for high resolution pectroscopy follow up.