Theoretical evolution of Rossby number for solar analog stars

• Main Authors: Castro, Matthieu, Duarte, Tharcísyo, Nascimento, José Dias do
• Format: Text
• Language: unknown
• Published: arXiv 2013
• Subjects: Solar and Stellar Astrophysics astro-ph.SR; FOS Physical sciences; narval
• Online Access: https://dx.doi.org/10.48550/arxiv.1309.7974; https://arxiv.org/abs/1309.7974

Magnetic fields of late-type stars are presumably generated by a dynamo mechanism at the interface layer between the radiative interior and the outer convective zone. The Rossby number, which is related to the dynamo process, shows an observational correlation with activity. It represents the ratio between the rotation period of the star and the local convective turnover time. The former is well determined from observations but the latter is estimated by an empirical iterated function depending on the color index (B-V) and the mixing-length parameter. We computed the theoretical Rossby number of stellar models with the TGEC code, and analyze its evolution with time during the main sequence. We estimated a function for the local convective turnover time corresponding to a mixing-length parameter inferred from a solar model, and compare our results to the estimated Rossby number of 33 solar analogs and twins, observed with the spectropolarimeters ESPaDOnS@CFHT and Narval@LBT. : 2 pages, 2 figures, conference publication of "IAUS 302: Magnetic fields throughout stellar evolution"