The GAPS programme with HARPS-N at TNG
IV. A planetary system around XO-2S
S. Desidera, A. S. Bonomo, R. Claudi, M. Damasso, K. Biazzo, A. Sozzetti, F. Marzari, S. Benatti, D. Gandolfi, R. Gratton, A. F. Lanza, V. Nascimbeni, G. Andreuzzi, L. Affer, M. Barbieri, L. Bedin, A. Bignamini, M. Bonavita, F. Borsa, P. Calcidese, J. M. Christille, R. Cosentino, E. Covino, M. Esposito, P. Giacobbe, H. Avet, D. W. Latham, M. Lattanzi, G. Leto, G. Lodato, C. Lovis, A. Maggio, L. Malavolta, L. Mancini, A. F. Martinez Fiorenziano, G. Micela, E. Molinari, C. Mordasini, U. Munari, I. Pagano, M. Pedani, F. Pepe, G. Piotto, E. Poretti, M. Rainer, I. Ribas, N. C. Santos, G. Scandariato, R. Silvotti, J. Southworth, R. Zanmar Sanchez
We performed an intensive radial velocity monitoring of XO-2S, the wide companion of the transiting planet-host XO-2N, using HARPS-N at TNG in the framework of the GAPS programme. The radial velocity measurements indicate the presence of a new planetary system formed by a planet that is slightly more massive than Jupiter at 0.48 au and a Saturn-mass planet at 0.13 au. Both planetary orbits are moderately eccentric and were found to be dynamically stable. There are also indications of a long-term trend in the radial velocities. This is the first confirmed case of a wide binary whose components both host planets, one of which is transiting, which makes the XO-2 system a unique laboratory for understanding the diversity of planetary systems.
techniques: radial velocities - planetary systems - stars: individual: XO-2S - stars: individual: XO-2N
Astronomy and Astrophysics
Volume 567, Page L6_1
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