CoRoT reveals a magnetic activity cycle in a Sun-like star

Rafael A. García (1) , Savita Mathur (2) , David Salabert (3) , Jérôme Ballot (4) , Clara Régulo (3) , Travis S. Metcalfe (2) , Annie Baglin (5)

1 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
2 HAO - High Altitude Observatory
3 IAC - Instituto de Astrofisica de Canarias
4 LATT - Laboratoire Astrophysique de Toulouse-Tarbes
5 LESIA (UMR_8109) - Laboratoire d'études spatiales et d'instrumentation en astrophysique

The 11-year activity cycle of the Sun is a consequence of a dynamo process occurring beneath its surface. We analyzed photometric data obtained by the CoRoT space mission, showing solarlike oscillations in the star HD49933, for signatures of stellar magnetic activity. Asteroseismic measurements of global changes in the oscillation frequencies and mode amplitudes reveal a modulation of at least 120 days, with the minimum frequency shift corresponding to maximum amplitude as in the Sun. These observations are evidence of a stellar magnetic activity cycle taking place beneath the surface of HD49933 and provide constraints for stellar dynamo models under conditions different from those of the Sun

Domaines: Astrophysique stellaire et solaire [astro-ph.SR]

Rafael A. García, Savita Mathur, David Salabert, Jérôme Ballot, Clara Régulo, et al.. CoRoT reveals a magnetic activity cycle in a Sun-like star. Science, 2010, 329 (5995), pp.1032. ⟨10.1126/science.1191064⟩. ⟨cea-00865988⟩