Models of red giants in the CoRoT asteroseismology fields combining asteroseismic and spectroscopic constraints

Autor(en)

N. Lagarde, A. Miglio, P. Eggenberger, T. Morel, J. Montalban, Thomas Kallinger, Markus Hareter

Abstrakt

Context: The availability of asteroseismic constraints for a large sample of red giant stars from the CoRoT and Kepler missions paves the way for various statistical studies of the seismic properties of stellar populations.
Aims: We use a detailed spectroscopic study of 19 CoRoT red giant stars to compare theoretical stellar evolution models to observations of the open cluster NGC 6633 and field stars.
Methods: In order to explore the effects of rotation-induced mixing and thermohaline instability, we compare surface abundances of carbon isotopic ratio and lithium with stellar evolution predictions. These chemicals are sensitive to extra-mixing on the red giant branch.
Results: We estimate mass, radius, and distance for each star using the seismic constraints. We note that the Hipparcos and seismic distances are different. However, the uncertainties are such that this may not be significant. Although the seismic distances for the cluster members are self consistent they are somewhat larger than the Hipparcos distance. This is an issue that should be considered elsewhere. Models including thermohaline instability and rotation-induced mixing, together with the seismically determined masses can explain the chemical properties of red giant targets. However, with this sample of stars we cannot perform stringent tests of the current stellar models. Tighter constraints on the physics of the models would require the measurement of the core and surface rotation rates, and of the period spacing of gravity-dominated mixed modes. A larger number of stars with longer times series, as provided by Kepler or expected with Plato, would help ensemble asteroseismology.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

University of Birmingham, Aarhus University, Universität Genf, Università degli Studi di Padova, Université de Liège

Journal

Astronomy & Astrophysics

Band

580

Anzahl der Seiten

14

ISSN

0004-6361

DOI

https://doi.org/10.1051/0004-6361/201525856

Publikationsdatum

08-2015

Peer-reviewed

Ja

ÖFOS 2012

103003 Astronomie, 103004 Astrophysik

Schlagwörter

ASJC Scopus Sachgebiete

Astronomy and Astrophysics, Space and Planetary Science

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/models-of-red-giants-in-the-corot-asteroseismology-fields-combining-asteroseismic-and-spectroscopic-constraints(da2f92ae-c9e8-408f-af38-bec24da0f0a9).html