Photometric Variability of Low Mass Stars and Brown Dwarfs in IC 348 and Taurus Star-Forming Regions

Abstract

Low-mass stars belonging to the M spectral type are the most numerous stars in our Galaxy, amounting to about two-thirds in number, and are found at the bottom of the main sequence in the H-R diagram. Photometric studies of low-mass stars, including brown dwarfs (Bds), provide several important evolutions of their atmosphere, magnetic flares and chromospheric activity. This paper highlights a few interesting results from our optical I-band observations of 2MASS J03435638+3209591 in the young star-forming IC 348 region and three BDs in Taurus star-forming regions using ground-based telescopes as well as a space-based telescope. We estimated the fast periodicities in the range of 1.5 to 3 hours in Taurus BDs. Furthermore, using the long-term photometry from the Transiting Exoplanet Survey Satellite (TESS), we have conducted a time-resolved variability analysis of CFHT-BD-Tau 4. The periodogram analysis of TESS data reveals an orbital period of ∼ 3 days. We found two flare events in TESS sector 43 data for this BD and estimated the flared energies as 4.59×1035 erg and 2.64×1036 erg, which sit in the superflare range.