Free access
Volume 440, Number 2, September III 2005
Page(s) 751 - 758
Section Planets and planetary systems

A&A 440, 751-758 (2005)
DOI: 10.1051/0004-6361:20042376

The CORALIE survey for southern extra-solar planets

XIII. A pair of planets around HD 202206 or a circumbinary planet?
A. C. M. Correia1, 2, 3, S. Udry1, M. Mayor1, J. Laskar3, D. Naef4, F. Pepe1, D. Queloz1 and N. C. Santos1, 5

1  Observatoire de Genève, 51 Ch. des Maillettes, 1290 Sauverny, Switzerland
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

(Received 17 November 2004 / 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 $m_2\sin
i=17.4~M_{\rm Jup}$ and $2.44~M_{\rm Jup}$, 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.

Key words: techniques: radial velocities -- techniques: spectroscopic -- stars: individual: HD 202206 -- stars: binaries: general -- stars: planetary systems

SIMBAD Objects

© ESO 2005