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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 720285.0, MPI für Astronomie / Publikationen_mpia
The GAPS programme with HARPS-N at TNG. V. A comprehensive analysis of the XO-2 stellar and planetary systems
Authors:Damasso, M.; Biazzo, K.; Bonomo, A. S.; Desidera, S.; Lanza, A. F.; Nascimbeni, V.; Esposito, M.; Scandariato, G.; Sozzetti, A.; Cosentino, R.; Gratton, R.; Malavolta, L.; Rainer, M.; Gandolfi, D.; Poretti, E.; Zanmar Sanchez, R.; Ribas, I.; Santos, N.; Affer, L.; Andreuzzi, G.; Barbieri, M.; Bedin, L. R.; Benatti, S.; Bernagozzi, A.; Bertolini, E.; Bonavita, M.; Borsa, F.; Borsato, L.; Boschin, W.; Calcidese, P.; Carbognani, A.; Cenadelli, D.; Christille, J. M.; Claudi, R. U.; Covino, E.; Cunial, A.; Giacobbe, P.; Granata, V.; Harutyunyan, A.; Lattanzi, M. G.; Leto, G.; Libralato, M.; Lodato, G.; Lorenzi, V.; Mancini, L.; Martinez Fiorenzano, A. F.; Marzari, F.; Masiero, S.; Micela, G.; Molinari, E.; Molinaro, M.; Munari, U.; Murabito, S.; Pagano, I.; Pedani, M.; Piotto, G.; Rosenberg, A.; Silvotti, R.; Southworth, J.
Date of Publication (YYYY-MM-DD):2015
Title of Journal:Astronomy and Astrophysics
Start Page:id. A111 (24 pp)
Audience:Not Specified
Abstract / Description:<BR /> Aims: XO-2 is the first confirmed wide stellar binary system where the almost twin components XO-2N and XO-2S have planets, and it is a peculiar laboratory in which to investigate the diversity of planetary systems. This stimulated a detailed characterization study of the stellar and planetary components based on new observations. <BR /> Methods: We collected high-resolution spectra with the HARPS-N spectrograph and multi-band light curves. Spectral analysis led to an accurate determination of the stellar atmospheric parameters and characterization of the stellar activity, and high-precision radial velocities of XO-2N were measured. We collected 14 transit light curves of XO-2Nb used to improve the transit parameters. Photometry provided accurate magnitude differences between the stars and a measure of their rotation periods. <BR /> Results: The iron abundance of XO-2N was found to be +0.054 dex greater, within more than 3σ, than that of XO-2S. The existence of a long-term variation in the radial velocities of XO-2N is confirmed, and we detected a turnover with respect to previous measurements. We suggest the presence of a second massive companion in an outer orbit or the stellar activity cycle as possible causes of the observed acceleration. The latter explanation seems more plausible with the present dataset. We obtained an accurate value of the projected spin-orbit angle for the XO-2N system (λ = 7° ± 11°), and estimated the real 3D spin-orbit angle (ψ =27+12-27 degrees). We measured the XO-2 rotation periods, and found a value of P = 41.6 ± 1.1 days in the case of
Free Keywords:stars: individual: XO-2; stars: fundamental parameters; stars: abundances; planetary systems; techniques: radial velocities; techniques: photometric
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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