2015A&A...580A..96D


C.D.S. - SIMBAD4 rel 1.7 - 2021.03.05CET12:24:39

2015A&A...580A..96D - Astronomy and Astrophysics, volume 580A, 96-96 (2015/8-1)

Seismic evidence for a weak radial differential rotation in intermediate-mass core helium burning stars.

DEHEUVELS S., BALLOT J., BECK P.G., MOSSER B., OSTENSEN R., GARCIA R.A. and GOUPIL M.J.

Abstract (from CDS):

The detection of mixed modes that are split by rotation in Kepler red giants has made it possible to probe the internal rotation profiles of these stars, which brings new constraints on the transport of angular momentum in stars. Rotation rates in the central regions of intermediate-mass core helium burning stars (secondary clump stars) have recently been measured. Our aim is to exploit the rotational splittings of mixed modes to estimate the amount of radial differential rotation in the interior of secondary clump stars using Kepler data in order to place constraints on angular momentum transport in intermediate-mass stars. We select a subsample of Kepler secondary clump stars with mixed modes that are clearly rotationally split. By applying a thorough statistical analysis, we show that the splittings of gravity-dominated modes (trapped in central regions) and of p-dominated modes (trapped in the envelope) can be measured. We then use these splittings to estimate the amount of differential rotation by using inversion techniques and by applying a simplified approach based on asymptotic theory. We obtain evidence for a weak radial differential rotation for six of the seven targets that were selected, with the central regions rotating from 1.8±0.3 to 3.2±1.0 times faster than the envelope. The last target is found to be consistent with a solid-body rotation. This demonstrates that an efficient redistribution of angular momentum occurs after the end of the main sequence in the interior of intermediate-mass stars, either during the short-lived subgiant phase or once He-burning has started in the core. In either case, this should bring constraints on the angular momentum transport mechanisms that are at work.

Abstract Copyright:

Journal keyword(s): stars: oscillations - stars: rotation - stars: evolution

Simbad objects: 7

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Number of rows : 7

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 2MASS J18410298+4315506 RG* 18 41 02.9846808320 +43 15 50.643252589   12.56 11.54     G6V 19 0
2 2MASS J19231435+3852566 RG* 19 23 14.3564748705 +38 52 56.483832818   11.77 10.62     ~ 15 0
3 2MASS J19234842+4020362 RG* 19 23 48.4268507404 +40 20 36.177834091   11.16 10.10     ~ 12 0
4 2MASS J19324955+3945234 RG* 19 32 49.5536835360 +39 45 23.476458668   12.35 11.66     G8III 13 0
5 KIC 9346602 Er* 19 34 05.1752764498 +45 51 49.670239792   11.72 10.81     ~ 15 0
6 KIC 8962923 RG* 19 40 56.8466896948 +45 16 05.089921290   11.99 11.22     G8III 17 0
7 2MASS J19501503+4305506 RG* 19 50 15.0424212768 +43 05 50.695880456   11.46 10.47     ~ 12 0

    Equat.    Gal    SGal    Ecl

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2021.03.05-12:24:39

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