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arXiv · astro-ph/9908038

Gravitational Microlensing Evidence for a Planet Orbiting a Binary Star System

D. P. Bennett·S. H. Rhie·A. C. Becker·N. Butler·J. Dann·S. Kaspi·E. M. Leibowitz·Y. Lipkin·D. Maoz·H. Mendelson·B. A. Peterson·J. Quinn·O. Shemmer·S. Thomson·S. E. Turner
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Abstract

The study of extra-solar planetary systems has emerged as a new discipline of observational astronomy in the past few years with the discovery of a number of extra-solar planets. The properties of most of these extra-solar planets were not anticipated by theoretical work on the formation of planetary systems. Here we report observations and light curve modeling of gravitational microlensing event MACHO-97-BLG-41, which indicates that the lens system consists of a planet orbiting a binary star system. According to this model, the mass ratio of the binary star system is 3.8:1 and the stars are most likely to be a late K dwarf and an M dwarf with a separation of about 1.8 AU. A planet of about 3 Jupiter masses orbits this system at a distance of about 7 AU. If our interpretation of this light curve is correct, it represents the first discovery of a planet orbiting a binary star system and the first detection of a Jovian planet via the gravitational microlensing technique. It suggests that giant planets may be common in short period binary star systems.

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D. P. Bennett, S. H. Rhie, A. C. Becker, N. Butler, J. Dann, S. Kaspi, E. M. Leibowitz, Y. Lipkin, D. Maoz, H. Mendelson, B. A. Peterson, J. Quinn, O. Shemmer, S. Thomson, S. E. Turner. 1999-11-04. Gravitational Microlensing Evidence for a Planet Orbiting a Binary Star System. https://doi.org/10.1038/46990

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