Starspots Modelling and Flare Analysis on Selected MV Stars

TL;DR

This study models stellar spots and analyzes flare activity on selected M dwarf stars using TESS data, introducing new software tools for light curve modeling and flare detection, revealing complex spot configurations and flare distributions.

Contribution

The paper presents original software for spot modeling (BASSMAN) and flare detection (WARPFINDER), applied to TESS data of M dwarf stars, advancing methods for stellar activity analysis.

Findings

Identified two spots on GJ 1243 with 2800K temperature and 3-4% spottedness.

Detected two spots on V374 Peg with 3000K temperature and 6% spottedness.

Found non-homogeneous flare distributions and correlations with spots on YZ CMi and GJ 1243.

Abstract

We studied light curves of GJ 1243, YZ CMi, and V374 Peg, observed by TESS for the presence of stellar spots and stellar flares. One of the main goals was to model light curves of spotted stars to estimate the number of spots along with their parameters using our original BASSMAN software. The modeled light curves were subtracted from the observations to increase efficiency of flare detection. Flares were detected automatically with our new dedicated software WARPFINDER. We estimated the presence of two spots on GJ 1243 with mean temperature about 2800$\,$K and spottedness varying between $3\%-4\%$ of the stellar surface and two spots on V374 Peg with a mean temperature of about 3000$\,$K and spottedness about 6$\%$ of the stellar surface. On YZ CMi we found two different models for two light curves separated in time by one and a half year. One of them is three-spot model with mean temperature of about 3000$\,$K and spottedness of star about 9$\%$ of the stellar surface. The second is a four-spot model with mean temperature about 2800$\,$K and spottedness about 7$\%$ of the stellar surface. We tested whether the flares are distributed homogeneously in phase and if there is any correlation between the presence of spots and the distribution of flares. For YZ CMi one spot is in anticorrelation with the distribution of the flares and for GJ 1243 shows non-homogeneous distribution of flares.