Bibcode
Triana, S. A.; Corsaro, E.; De Ridder, J.; Bonanno, A.; Perez-Hernandez, F.; García, R. A.
Bibliographical reference
Astronomy and Astrophysics, Volume 602, id.A62, 16 pp.
Advertised on:
6
2017
Journal
Citations
42
Refereed citations
37
Description
Context. The Kepler space telescope has provided time series of red
giants of such unprecedented quality that a detailed asteroseismic
analysis becomes possible. For a limited set of about a dozen red
giants, the observed oscillation frequencies obtained by peak-bagging
together with the most recent pulsation codes allowed us to reliably
determine the core/envelope rotation ratio. The results so far show that
the current models are unable to reproduce the rotation ratios,
predicting higher values than what is observed and thus indicating that
an efficient angular momentum transport mechanism should be at work.
Here we provide an asteroseismic analysis of a sample of 13
low-luminosity low-mass red giant stars observed by Kepler during its
first nominal mission. These targets form a subsample of the 19 red
giants studied previously, which not only have a large number of
extracted oscillation frequencies, but also unambiguous mode
identifications. Aims: We aim to extend the sample of red giants
for which internal rotation ratios obtained by theoretical modeling of
peak-bagged frequencies are available. We also derive the rotation
ratios using different methods, and compare the results of these methods
with each other. Methods: We built seismic models using a grid
search combined with a Nelder-Mead simplex algorithm and obtained
rotation averages employing Bayesian inference and inversion methods. We
compared these averages with those obtained using a previously developed
model-independent method. Results: We find that the cores of the
red giants in this sample are rotating 5 to 10 times faster than their
envelopes, which is consistent with earlier results. The rotation rates
computed from the different methods show good agreement for some
targets, while some discrepancies exist for others.
Related projects
Helio and Astero-Seismology and Exoplanets Search
The principal objectives of this project are: 1) to study the structure and dynamics of the solar interior, 2) to extend this study to other stars, 3) to search for extrasolar planets using photometric methods (primarily by transits of their host stars) and their characterization (using radial velocity information) and 4) the study of the planetary
Savita
Mathur