A calibration of the Rossby number from asteroseismology
Journal
Date Issued
2021
Author(s)
•
•
Mathur, S.
•
García, R. A.
•
Santos, A. R. G.
•
Breton, S. N.
•
Khalatyan, A.
Abstract
Stellar activity and rotation are tightly related in a dynamo process. Our
understanding of this mechanism is mainly limited by our capability of
inferring the properties of stellar turbulent convection. In particular, the
convective turnover time is a key ingredient through the estimation of the
stellar Rossby number, which is the ratio of the rotation period and the
convective turnover time. In this work we propose a new calibration of the
$(B-V)$ color index dependence of the convective turnover time, hence of the
stellar Rossby number. Our new calibration is based on the stellar structure
properties inferred through the detailed modeling of solar-like pulsators using
asteroseismic observables. We show the impact of this calibration in a stellar
activity -- Rossby number diagram by applying it to a sample of about 40,000
stars observed with Kepler and for which photometric activity proxy
$S_\mathrm{\!ph}$ and surface rotation periods are available. Additionally, we
provide a new calibration of the convective turnover time as function of the
$(G_\mathrm{BP}-G_\mathrm{RP})$ color index for allowing applicability in the
ESA Gaia photometric passbands.
Volume
652
Start page
L2
Issn Identifier
0004-6361
Ads BibCode
2021A&A...652L...2C
Rights
open.access
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