2025ApJ...981..169K


Query : 2025ApJ...981..169K

2025ApJ...981..169K - Astrophys. J., 981, 169 (2025/March-2)

Starspot Distribution and Flare Events in Two Young Low-mass Stars Using TESS Data.

KUMBHAKAR R., MONDAL S., GHOSH S. and RAM D.

Abstract (from CDS):

Wide-field high-precision photometric observations such as the Transiting Exoplanet Survey Satellite (TESS) allowed the investigation of the stellar magnetic activity of cool stars. M dwarf starspots and stellar flares are the main indicators of magnetic activity. The present study focuses on modeling light curves (LCs) to analyze the distribution and characteristics of starspots, e.g., location, temperature, and spot size. The TESS LCs of two selected young M dwarfs, i.e., GJ 182 and 2MASS J05160212+2214528, were reconstructed using the Best rAndom StarSpots Model calculAtioN software, obtaining a three-spot model for GJ 182 and two-spot model for 2MASS J05160212+2214528, describing their LCs. For GJ 182, the mean spot temperature was estimated to be approximately 3279 K, covering 5%-8.5% of the stellar surface, while for 2MASS J05160212+2214528, the average spot temperature was approximately 2631 K, with a mean spottedness of about 5.4%. Using the 2 minute cadence LC data, we identified and analyzed 48 flare events from GJ 182, while no flares were detected in 2MASS J05160212+2214528. The estimated bolometric flare energy ranges from 1032 to 1035 erg, while in the TESS bandpass, it ranges from 1031 to 1033 erg. We derived the power-law index of -1.53 ± 0.12 and -1.86 ± 0.22 for flare frequency distribution in sectors 5 and 32, respectively, in the flare energy range 1033-1035 erg, consistent with previous studies for M dwarfs. A positive linear correlation between flare energy and duration was found with a slope of 0.67 ± 0.02, suggesting a similar mechanism followed by stellar superflares and solar flares. By assuming the similarities with solar flares, we also estimated a lower limit of the magnetic field strength of around 12-232 G to produce such superflare events.

Abstract Copyright: © 2025. The Author(s). Published by the American Astronomical Society.

Journal keyword(s): Variable stars - Starspots - Stellar flares - M dwarf stars - Stellar activity - Stellar rotation

Simbad objects: 10

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Number of rows : 10
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026
#notes
1 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 4971 0
2 V* V1005 Ori BY* 04 59 34.8342878424 +01 47 00.669818328   11.48 10.107 9.603 8.239 M0Ve 371 0
3 2MASS J05160212+2214528 TT* 05 16 02.1235848768 +22 14 52.853970012   17.4   15.9 14.1 M5 10 0
4 * alf Ori s*r 05 55 10.30536 +07 24 25.4304 4.38 2.27 0.42 -1.17 -2.45 M1-M2Ia-Iab 1789 0
5 V* YZ CMi PM* 07 44 40.1723046464 +03 33 08.875227574 13.761 12.831 11.225 9.958 8.263 M4.0Ve 957 0
6 Kepler-411 Er* 19 10 25.3469947368 +49 31 23.712634632   13.70 12.55 12.26   K3V 129 0
7 G 208-42 PM* 19 51 09.3205973189 +46 29 00.213809780   14.47   12.544   M4.0Ve 235 0
8 HD 197481 BY* 20 45 09.5324974119 -31 20 27.237889841   10.05 8.627 9.078 6.593 M1VeBa1 1344 0
9 V* V374 Peg PM* 22 01 13.1241989539 +28 18 24.907312662       11.602   M3.5Ve 259 0
10 V* EV Lac PM* 22 46 49.7312610268 +44 20 02.374381562   11.85 10.26 9.89   M4.0Ve 993 2

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