The CORALIE survey for southern extra-solar planets
XIII. A pair of planets around HD 202206 or a circumbinary planet?
Observatoire de Genève, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland e-mail: firstname.lastname@example.org
2 Departamento de Física da Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
3 Astronomie et Systèmes Dynamiques, IMCCE-CNRS UMR 8028, 77 avenue Denfert-Rochereau, 75014 Paris, France
4 European Southern Observatory, Casilla 19001, Santiago 19, Chile
5 Centro de Astronomia e Astrofísica da Universidade de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal
Accepted: 12 May 2005
Long-term precise Doppler measurements with the CORALIE spectrograph reveal the presence of a second planet orbiting the solar-type star HD 202206. The radial-velocity combined fit yields companion masses of and , semi-major axes of AU and 2.55 AU, and eccentricities of 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.
Key words: techniques: radial velocities / techniques: spectroscopic / stars: individual: HD 202206 / stars: binaries: general / stars: planetary systems
© ESO, 2005