Starspots Modelling and Flare Analysis on Selected MV Stars

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 2800K and spottedness varying between $3\%-4\%$ of the stellar surface and two spots on V374 Peg with a mean temperature of about 3000K 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 3000K and spottedness of star about 9$\%$ of the stellar surface. The second is a four-spot model with mean temperature about 2800K 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.

28 pages, 22 figures, accepted to ApJ

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• Numerical quantification of the wind properties of cool main sequence stars
• Stellar flare morphology with TESS across the main sequence
• Predicting Stellar Rotation Periods Using XGBoost
• Flaring Latitudes in Ensembles of Low Mass Stars
• Dynamic Photometric Variability in Three Young Brown Dwarfs in Taurus: Detection of Optical Flares with TESS data
• Unveiling the Variability and Chemical Composition of AL Col