Seismic Constraints on Rotation of Sun-like Stars and Exoplanet Mass

Rotation is thought to drive cyclic magnetic activity in the Sun and Sun-like stars. Stellar dynamos, however, are poorly understood owing to the scarcity of observations of rotation and magnetic fields in stars.

Here, inferences are drawn on the internal rotation of a distant Sun-like star by studying its global modes of oscillation. We report asteroseismic constraints imposed on the rotation rate and the inclination of the spin axis of the Sun-like star HD 52265, a principal target observed by the CoRoT satellite that is known to host a planetary companion. These seismic inferences are remarkably consistent with an independent spectroscopic observation (rotational line broadening) and with the observed rotation period of star spots. Furthermore, asteroseismology constrains the mass of exoplanet HD 52265b. Under the standard assumption that the stellar spin axis and the axis of the planetary orbit coincide, the minimum spectroscopic mass of the planet can be converted into a true mass of 1.85 (+0.52,-0.42) M_Jupiter, which implies that it is a planet, not a brown dwarf.

Laurent Gizon, Jerome Ballot, Eric Michel, Thorsten Stahn, Gerard Vauclair, Hans Bruntt, Pierre-Olivier Quirion, Othman Benomar, Sylvie Vauclair, Thierry Appourchaux, Michel Auvergne, Annie Baglin, Caroline Barban, Frederic Baudin, Michael Bazot, Tiago Campante, Claude Catala, William Chaplin, Orlagh Creevey, Sebastien Deheuvels, Noel Dolez, Yvonne Elsworth, Rafael Garcia, Patrick Gaulme, Stephane Mathis, Savita Mathur, Benoit Mosser, Clara Regulo, Ian Roxburgh, David Salabert, Reza Samadi, Kumiko Sato, Graham Verner, Shravan Hanasoge, Katepalli R. Sreenivasan
(Submitted on 20 Aug 2013)

Comments: Published in Proceedings of the National Academy of Sciences (5 pages, 5 figures, 3 tables). Available at this http URL

Subjects: Solar and Stellar Astrophysics (astro-ph.SR)

Journal reference: PNAS 2013, vol. 110, no. 33, pp. 13267-13271

DOI: 10.1073/pnas.1303291110

Cite as: arXiv:1308.4352 [astro-ph.SR] (or arXiv:1308.4352v1 [astro-ph.SR] for this version)

Submission history From: Laurent Gizon [view email]
[v1] Tue, 20 Aug 2013 17:08:24 GMT (250kb)