Title: Fast core rotation in red-giant stars as revealed by gravity-dominated mixed modes
Authors: P.G.Beck, Paul ×
Montalban, Josefina
Kallinger, Thomas
De Ridder, Joris
Aerts, Conny
Garcia, Rafael A.
Hekker, Saskia
Dupret, Marc-Antoine
Mosser, Benoit
Eggenberger, Patrick
Stello, Dennis
Elsworth, Yvonne
Frandsen, Soeren
Carrier, Fabien
Hillen, Michel
Gruberbauer, Michael
Christensen-Dalsgaard, Joergen
Miglio, Andrea
Valentini, Marica
Bedding, Timothy R.
Kjeldsen, Hans
Girouard, Forrest R.
Hall, Jennifer R.
Ibrahim, Khadeejah A. #
Issue Date: 5-Jan-2012
Publisher: Nature Publishing Group
Series Title: Nature vol:481 issue:7379 pages:55-57
Abstract: When the core hydrogen is exhausted during stellar evolution, the central region of a star contracts and the outer envelope expands and cools, giving rise to a red giant. Convection takes place over much of the star's radius. Conservation of angular momentum requires that the cores of these stars rotate faster than their envelopes; indirect evidence supports this. Information about the angular-momentum distribution is inaccessible to direct observations, but it can be extracted from the effect of rotation on oscillation modes that probe the stellar interior. Here we report an increasing rotation rate from the surface of the star to the stellar core in the interiors of red giants, obtained using the rotational frequency splitting of recently detected `mixed modes'. By comparison with theoretical stellar models, we conclude that the core must rotate at least ten times faster than the surface. This observational result confirms the theoretical prediction of a steep gradient in the rotation profile towards the deep stellar interior.
ISSN: 0028-0836
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Institute of Astronomy
× corresponding author
# (joint) last author

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