Characterisation of starspot structure and differential rotation of Kepler-411

TL;DR

This study analyzes Kepler-411's starspots and rotation using photometric modeling and planetary transits, revealing a rigid rotation profile and spot distributions, with three spots occulted by the planet.

Contribution

It introduces a combined approach of photometric spot modeling and transit mapping to characterize starspot distribution and rotation in Kepler-411, finding no differential rotation.

Findings

Starspots are well modeled by the methods used.

Kepler-411 exhibits rigid-body rotation with a period of about 10.52 days.

Three starspots were occulted by planet c, aligning with modeled spot locations.

Abstract

Starspots and their movements on stellar surfaces enable investigating the mechanisms of stellar magnetic activity. Information on the spot distribution and differential rotation provide important constraints for the behaviour of stellar magnetic dynamos. We analyse the Kepler photometry of Kepler-411, a known exoplanet host, to determine the distribution and properties of star spots on the stellar surface with two independent and complementary methods: modelling the photometric effect of rotation of spots on the stellar surface and mapping of spots by transiting planets. By constructing a spot model accounting for geometry, differential rotation and spot evolution, we model the spots of the stellar surface giving rise to the observed brightness variations. We also search for evidence for occultations of starspots in high-cadence photometry. Our spot models reproduce the observed photometric variations well and we are able to obtain information on the distribution and movement of spots on the stellar surface. We do not obtain evidence for differential rotation -- the rotational profile is consistent with rigid-body rotation with a period of 10.52$\pm$0.34 days. We detect three occultations of spots by planet c. The positions of these spots coincide well with the positions of larger spot structures identified by our modelling of the rotational modulation of the light curve.