Astronomy and Astrophysics – Astrophysics – Solar and Stellar Astrophysics
Scientific paper
2011-12-13
Astronomy and Astrophysics
Astrophysics
Solar and Stellar Astrophysics
to appear as a Letter to Nature
Scientific paper
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, in which convection occupies a large fraction of the star. Conservation of angular momentum requires that the cores of these stars rotate faster than their envelopes, and 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 the detection of non-rigid rotation in the interiors of red-giant stars by exploiting the rotational frequency splitting of recently detected mixed modes. We demonstrate an increasing rotation rate from the surface of the star to the stellar core. Comparing 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.
Aerts Conny
Beck Paul G.
Bedding Timothy R.
Carrier Fabien
Christensen-Dalsgaard Jørgen
No associations
LandOfFree
Fast core rotation in red-giant stars revealed by gravity-dominated mixed modes does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Fast core rotation in red-giant stars revealed by gravity-dominated mixed modes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fast core rotation in red-giant stars revealed by gravity-dominated mixed modes will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-486120