Volume 535, November 2011
|Number of page(s)||6|
|Section||Planets and planetary systems|
|Published online||03 November 2011|
A binary merger origin for inflated hot Jupiter planets
Centro de Astrobiologia CSIC – INTA, Carretera Torrejón-Ajalvir km
2 Max-Planck-Institut für Astrophysik, 85748 Garching, Germany
3 Instituto de Astrofisica de Canarias, calle Via Lactea, 38200 La Laguna, Tenerife, Spain
Received: 16 March 2011
Accepted: 27 August 2011
We hypothesize that hot Jupiters with inflated sizes represent a separate planet formation channel, the merging of two low-mass stars. We show that the abundance and properties of W UMa stars and low mass detached binaries are consistent with their being possible progenitors. The degree of inflation of the transiting hot Jupiters correlates with their expected spiral-in life time by tidal dissipation, and this could indicate youth if the stellar dissipation parameter Q∗' is sufficiently low. Several Jupiter-mass planets can form in the massive compact disk formed in a merger event. Gravitational scattering between them can explain the high incidence of excentric, inclined, and retrograde orbits. If the population of inflated planets is indeed formed by a merger process, their frequency should be much higher around blue stragglers than around T Tauri stars.
Key words: planets and satellites: formation / binaries: eclipsing / planets and satellites: dynamical evolution and stability / blue stragglers / methods: statistical
© ESO, 2011
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