An F-type ultra-fast rotator KIC 6791060: Starspot modulation and Flares

TL;DR

This study analyzes an ultra-fast rotating F-type star using Kepler data, revealing its rotation period, surface differential rotation, multiple starspot groups, and optical flares with high energies, indicating complex stellar activity.

Contribution

It provides detailed analysis of starspot modulation, differential rotation, and flare activity on KIC 6791060, a previously less-studied ultra-fast rotator.

Findings

Rotation period of 0.34365 days

Detection of 38 optical flares with energies up to 10^33 erg

Evidence of two active longitudes on the stellar surface

Abstract

Making use of the data obtained from Kepler satellite, we have analysed an F-type ultra-fast rotator KIC 6791060. We derive a rotational period of 0.34365$\pm$0.00004 d. Multiple periodicity with a period separation of $\sim$0.00016 d was detected, which appears to be a result of the relative velocity between the multiple spot-groups in different stellar latitudes due to surface differential rotation. During the observations, 38 optical flares are detected. Energies of these flares have been found to be in the range of $10^{31-33}$ erg. Preliminary results of surface temperature modeling indicate the existence of two active longitudes on the stellar surface.