OGLE-TR-3: A possible new transiting planet^*

¹ Institut für Astronomie und Astrophysik, Abt. Astronomie, Sand 1, 72076 Tübingen, Germany
² Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany
³ Institut für Astronomie und Astrophysik, Abt. Computational Physics, Auf der Morgenstelle 10, 72076 Tübingen, Germany
⁴ Dr.-Remeis-Sternwarte, Sternwartstraße 7, 96049 Bamberg, Germany
⁵ European Southern Observatory, Karl-Schwarzschild-Straße 2, 85748 Garching, Germany

Corresponding author: S. Dreizler dreizler@astro.uni-tuebingen.de

Received: 20 December 2002
Accepted: 19 February 2003

Abstract

Recently, 59 low-luminosity object transits were reported from the Optical Gravitational Lensing Experiment (OGLE). Our follow-up low-resolution spectroscopy of 16 candidates provided two objects, OGLE-TR-3 and OGLE-TR-10, which have companions with radii compatible with those of gas-giant planets. Further high-resolution spectroscopy revealed a very low velocity variation (< 500 m s^-1) of the host star OGLE-TR-3 which may be caused by its unseen companion. An analysis of the radial velocity and light curve results in , , and an orbital separation of about 5 , which makes it the planet with the shortest period known. This allows to identify the low-luminosity companion of OGLE-TR-3 as a possible new gas-giant planet. If confirmed, this makes OGLE-TR-3 together with OGLE-TR-56 the first extrasolar planets detected via their transit light curves.