Detailed Chromospheric Activity Nature of KIC 9641031

TL;DR

This paper investigates the chromospheric activity of the eclipsing binary KIC 9641031 using Kepler data, modeling rotational modulations, flares, and active regions, and finds that its activity level is relatively low compared to similar systems.

Contribution

It provides a detailed analysis of chromospheric activity, including flare modeling and active region configuration, revealing rapid changes and a correlation with orbital period variations.

Findings

One active component with two active regions separated by 180 degrees.

240 flares detected with a saturation level of 1.232 seconds.

Chromospheric activity correlates with orbital period variations.

Abstract

This study depends on KIC 9641031 eclipsing binary system with a chromospherically active component. There are three type variations, such as geometrical variations due to eclipses, sinusoidal variations due to the rotational modulations and also flares, in the light curves obtained with the data taken from the Kepler Mission Database. Taking into account results obtained from KIC 9641031's observations in the Kepler Mission Database, we present and discuss the details of chromospheric activity. The sinusoidal light variations due to rotational modulation and the flare events were modelled separately. 92 different data subsets separated using the analytic models described in the literature were modelled separately to obtain the cool spot configuration. It is seen that just one component of the system is chromospherically active star. On this component, there are two active regions separated by about 180 deg longitudinally between the latitudes of +50 deg and +100 deg, whose locations and forms are rapidly changing in short time intervals. 240 flares were detected and their parameters were computed. Using these parameters, the One Phase Exponential Association (hereafter OPEA) function model was derived, in which the Plateau value as a saturation level of the flare-equivalent duration was found to be 1.232 s for KIC 9641031, and half-life parameter was found to be 2291.7 s. The flare frequency N1 was found to be 0.41632 h-1, while the flare frequency N2 was found to be 0.00027. Considering these parameters together with the orbital period variations demonstrates that the period variations directly depend on chromospheric activity. Comparing the system with its analogue it is seen that the activity level of KIC 9641031 is remarkablely lower than the others.