Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 481 (7379), 55-7

Fast Core Rotation in Red-Giant Stars as Revealed by Gravity-Dominated Mixed Modes

Affiliations

Fast Core Rotation in Red-Giant Stars as Revealed by Gravity-Dominated Mixed Modes

Paul G Beck et al. Nature.

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.

Similar articles

See all similar articles

Cited by 4 PubMed Central articles

References

    1. Nature. 2011 Mar 31;471(7340):608-11 - PubMed
    1. Science. 2011 Apr 8;332(6026):205 - PubMed
    1. Science. 2007 Jun 15;316(5831):1591-3 - PubMed
    1. Science. 2003 Jun 20;300(5627):1926-8 - PubMed
    1. Nature. 2009 May 21;459(7245):398-400 - PubMed

Publication types

Feedback