Fast photometric variability of very low mass stars in IC 348: detection of superflare in an M dwarf. Issue 4 (18th November 2020)

• Record Type: Journal Article
• Authors: Ghosh, Samrat; Mondal, Soumen; Dutta, Somnath; Das, Ramkrishna; Joshi, Santosh; Lata, Sneh; Khata, Dhrimadri; Panja, Alik
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 500:Issue 4(2021)
• Page Start: 5106
• Page End: 5116
• Publication Date: 2020-11-18
• Subjects: methods: observational -- stars: atmospheres -- brown dwarfs -- stars: flare -- stars: low-mass -- stars: variables: general; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/staa3574
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We present here optical I -band photometric variability study down to ≃19 mag of a young (∼2–3 Myr) star-forming region IC 348 in the Perseus molecular cloud. We aim to explore the fast rotation (in the time-scales of hours) in very low-mass stars including brown dwarfs (BDs). From a sample of 177 light curves using our new I -band observations, we detect new photometric variability in 22 young M dwarfs including 6 BDs, which are bonafide members in IC 348 and well characterized in the spectral type of M dwarfs. Out of 22 variables, 11 M dwarfs including one BD show hour-scale periodic variability in the period range 3.5–11 h and rest are aperiodic in nature. Interestingly, an optical flare is detected in a young M2.75 dwarf in one night data on 2016 December 20. From the flare light curve, we estimate the emitted flared energy of 1.48 × 10 35 erg. The observed flared energy with an uncertainty of tens of per cent is close to the superflare range (∼10 34 erg), which is rarely observed in active M dwarfs.