Stellar activity, differential rotation, and exoplanets

TL;DR

This paper reviews stellar activity and differential rotation in stars with transiting planets observed by CoRoT, using spot modeling to analyze light curves and explore the influence of close-in planets on stellar behavior.

Contribution

It applies a solar irradiance-based spot model to CoRoT data, providing insights into stellar differential rotation and activity cycles in planet-hosting stars.

Findings

Spot migration indicates surface differential rotation.

Variations in spotted area suggest short-term activity cycles.

Potential influence of close-in planets on stellar activity.

Abstract

The photospheric spot activity of some of the stars with transiting planets discovered by the CoRoT space experiment is reviewed. Their out-of-transit light modulations are fitted by a spot model previously tested with the total solar irradiance variations. This approach allows us to study the longitude distribution of the spotted area and its variations versus time during the five months of a typical CoRoT time series. The migration of the spots in longitude provides a lower limit for the surface differential rotation, while the variation of the total spotted area can be used to search for short-term cycles akin the solar Rieger cycles. The possible impact of a close-in giant planet on stellar activity is also discussed.