Short-lived spots in solar-like stars as observed by CoRoT

TL;DR

This study analyzes high-quality CoRoT light curves of four solar-like stars to model short-lived spots, revealing insights into their rotation, spot lifetimes, and differential rotation with a simple iterative approach.

Contribution

The paper introduces a simple iterative spot modeling method with relaxation and Monte-Carlo simulations to accurately determine starspot parameters from CoRoT data.

Findings

Spot lifetimes are 0.5 to 2 times the rotation period.

Clear evidence of differential rotation in the stars.

Modeling results agree with other established methods.

Abstract

Context. CoRoT light curves have an unprecedented photometric quality, having simultaneously a high signal-to-noise ratio, a long time span and a nearly continuous duty-cycle. Aims. We analyse the light-curves of four bright targets observed in the seismology field and study short-lived small spots in solar-like stars. Methods. We present a simple spot modeling by iterative analysis. Its ability to extract relevant parameters is ensured by implementing relaxation steps to avoid convergence to local minima of the sum of the residuals between observations and modeling. The use of Monte-Carlo simulations allows us to estimate the performance of the fits. Results. Our starspot modeling gives a representation of the spots on these stars in agreement with other well tested methods. Within this framework, parameters such as rigid-body rotation and spot lifetimes seem to be precisely determined. Then, the lifetime/rotation period ratios are in the range 0.5 - 2, and there is clear evidence for differential rotation.