C. Moutou, G. Hébrard, F. Bouchy, L. Arnold, N. C. Santos, N. Astudillo, I. Boisse, X. Bonfils, S. Borgniet, X. Delfosse, R. F. Díaz, D. Ehrenreich, T. Forveille, J. Gregorio, O. Labrevoir, A.-M. Lagrange, G. Montagnier, M. Montalto, F. Pepe, J. Sahlmann, A. Santerne, D. Ségransan, S. Udry, M. Vanhuysse

Abstract
We present high-precision radial-velocity measurements of three solar-type stars: HD13908, HD159243, and HIP 91258. The observations were made with the SOPHIE spectrograph at the 1.93-m telescope of Observatoire de Haute-Provence (France). They show that these three bright stars host exoplanetary systems composed of at least two companions. HD13908 b is a planet with a minimum mass of 0.865±0.035 M_Jup on a circular orbit with a period of 19.382±0.006 days. There is an outer massive companion in the system with a period of 931±17 days, e = 0.12±0.02, and a minimum mass of 5.13±0.25 M_Jup. The star HD159243 also has two detected companions with respective masses, periods, and eccentricities of M_p = 1.13±0.05 and 1.9±0.13M_Jup, P = 12.620±0.004 and 248.4±4.9 days, and e = 0.02±0.02 and 0.075±0.05. Finally, the star HIP 91258 has a planetary companion with a minimum mass of 1.068±0.038 M_Jup, an orbital period of 5.0505±0.0015 days, and a quadratic trend indicating an outer planetary or stellar companion that is as yet uncharacterized. The planet-hosting stars HD13908, HD159243, and HIP 91258 are main-sequence stars of spectral types F8V, G0V, and G5V, respectively, with moderate activity levels. HIP 91258 is slightly over-metallic, while the two other stars have solar-like metallicity. The three systems are discussed in the frame of formation and dynamical evolution models of systems composed of several giant planets.

Keywords
Planetary systems – Techniques: radial velocities – Techniques: photometry – Stars: individual: HD13908, HD159243, HIP 91258

Astronomy & Astrophysics
Volume 563, Number of pages A22_1
2014 March

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