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A pair of planets around HD 202206 or a circumbinary planet?

A. C. M. Correia, S. Udry, M. Mayor, J. Laskar, D. Naef, F. Pepe, D. Queloz, N. C. Santos

astro-pharXiv:astro-ph/0411512

Abstract

Long-term precise Doppler measurements with the CORALIE spectrograph reveal the presence of a second planet orbiting the solar-type star HD202206. The radial-velocity combined fit yields companion masses of m2 = 17.4 MJup and 2.44 MJup, semi-major axes of a = 0.83 AU and 2.55 AU, and eccentricities of e = 0.43 and 0.27, respectively. A dynamical analysis of the system further shows a 5/1 mean motion resonance between the two planets. This system is of particular interest since the inner planet is within the brown-dwarf limits while the outer one is much less massive. Therefore, either the inner planet formed simultaneously in the protoplanetary disk as a superplanet, or the outer Jupiter-like planet formed in a circumbinary disk. We believe this singular planetary system will provide important constraints on planetary formation and migration scenarios.

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