Kinematics of metalrich stars with and without planets

Alexandra Ecuvillon,1 Garik Israelian,1 Frédéric Pont,2 Nuno C. Santos2'3'4

& Michel Mayor2

1 Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife, Spain 2Observatoire de Geneve, 51 Chemin des Maillettes, CH-1290 Sauverny, Switzerland 3 Observatorio Astronomico de Lisboa, 1349-018 Lisboa, Portugal 4 Centro de Geofísica de Evora, Rua Romao Ramalho 59, 7000 Evora, Portugal

We present a detailed study on the kinematics of metal-rich stars with and without planets, and their relation with the Hyades, Sirius and Hercules dynamical streams in the Solar neighbourhood. We compare the kinematic behaviour of known planet-host stars with that of the remaining targets belonging to the CORALIE volume-limited sample, in particular its metal-rich population. The high average metallicity of the Hyades stream is confirmed. The planet-host targets exhibit a kinematic behaviour similar to that of the metal-rich comparison subsample, rather than to that of the comparison sample as a whole, thus supporting the hypothesis of a primordial origin for the metal excess observed in stars with known planetary companions. According to the scenarios proposed as an explanation for the dynamical streams, systems with giant planets could have formed more easily in metal-rich inner Galactic regions

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