High-Level Magnetic Activity on a Low-Mass Close Binary: GSC 02038-0293

TL;DR

This study investigates the magnetic activity and light-curve behavior of the low-mass binary GSC 02038-0293 over multiple years, revealing active longitudes, spot migration, and a long-term brightness decrease.

Contribution

It provides detailed light-curve analysis, spot modeling, and long-term magnetic activity behavior of GSC 02038-0293, including the first clear detection of the secondary minimum in 2008.

Findings

Identification of two active longitudes with migrating spots.

Detection of a ~8.9-year sinusoidal variation in out-of-eclipse amplitude.

Observation of a significant decrease in the system's mean brightness over time.

Abstract

Taking into account results obtained from light-curve analysis and out-of-eclipse analyses, we discuss the nature of GSC 02038-00293 and also its magnetic activity behaviour. We obtained light curves of the system during observing seasons 2007, 2008 and 2011. We obtained its secondary minimum clearly in I-band observations in 2008 for the first time. Analysing this light curve, we found the physical parameters of the components. The light-curve analysis indicates that the possible mass ratio of the system is 0.35. We obtained the remaining V-band light curves, extracting the eclipses. We modelled these remaining curves using the spotmodel program and found possible spot configurations of the magnetically active component for each observing season. The models demonstrated that there are two active longitudes for the active component. The models reveal that both active longitudes migrate in the direction of decreasing longitude. We also examined the light curves in out-of-eclipse phases with respect to minimum and maximum brightness, amplitude, etc. The amplitude of the curves during out-of-eclipse phases varies in a sinusoidal way with a period of ~8.9yr the mean brightness of the system is dramatically decreasing. The phases of the deeper minimum during out-of-eclipse periods exhibit a migration toward decreasing phase.