Understanding angular momentum transport in red giants: the case of KIC 7341231
Résumé
Context. Thanks to recent asteroseismic observations, it has been
possible to infer the radial differential rotation profile of subgiants and red
giants.Aims. We want to reproduce the observed rotation profile of the early
red giant KIC 7341231 through modeling and constrain the physical mechanisms responsible
for angular momentum transport in stellar interiors.Methods. We computed models of KIC 7341231 including a treatment of
shellular rotation, and we compared the rotation profiles obtained with the one derived
from observations. We then modify some modeling parameters in order to quantify their
effect on the obtained rotation profile. Moreover, we mimicked a powerful angular momentum
transport during the main sequence and studied its effect on the evolution of the rotation
profile during the subgiant and red giant phases.Results. We show that meridional circulation and shear mixing alone
produce a rotation profile for KIC 7341231 that is too steep compared to the observed one.
An additional mechanism is then needed to increase the internal transport of angular
momentum. We find that this undetermined mechanism has to be efficient not only during the
main sequence but also during the much quicker subgiant phase. Moreover, we point out the
importance of studying the whole rotational history of a star to explain its rotation
profile during the red giant evolution.
Domaines
Astrophysique [astro-ph]
Origine : Publication financée par une institution
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