Simultaneous Detection of Optical Flares of the Magnetically Active M Dwarf Wolf 359

Abstract

We present detections of stellar flares of Wolf\,359, an M6.5 dwarf in the solar neighborhood (2.41~pc) known to be prone to flares due to surface magnetic activity. The observations were carried out from 2020 April 23 to 29 with a 1-m and a 0.5-m telescope separated by nearly 300~km in Xinjiang, China. In 27~hr of photometric monitoring, a total of 13 optical flares were detected, each with a total energy of $\gtrsim 5\times 10^{29}$~erg. The measured event rate of about once every two hours is consistent with those reported previously in radio, X-ray and optical wavelengths for this star. One such flare, detected by both telescopes on 26 April, was an energetic event with a released energy of nearly $10^{33}$~erg. The two-telescope lightcurves of this major event sampled at different cadences and exposure timings enabled us to better estimate the intrinsic flare profile, which reached a peak of up to 1.6 times the stellar quiescent brightness, that otherwise would have been underestimated in the observed flare amplitudes of about $0.4$ and $0.8$, respectively, with single telescopes alone. The compromise between fast sampling so as to resolve a flare profile versus a longer integration time for higher photometric signal-to-noise provides a useful guidance in the experimental design of future flare observations.

16 pages, 10 figures, 3 tables

References in corpus (5)

• The Transiting Exoplanet Survey Satellite
• Kepler Flares I. Active and Inactive M dwarfs
• Kepler Flares II: The Temporal Morphology of White-Light Flares on GJ 1243
• Characteristic time of stellar flares on Sun-like stars
• Time-resolved UVES observations of a stellar flare on the planet host HD 189733 during primary transit

Cited by in corpus (4)

• AU Microscopii in the FUV: Observations in Quiescence, During Flares, and Implications for AU Mic b and c
• The JCMT Transient Survey: Single Epoch Transients and Variability of Faint Sources
• Minute-cadence Observations of the LAMOST Fields with the TMTS: III. Statistic Study of the Flare Stars from the First Two Years
• Analysis of Solar-like X-Class Flare on Wolf 359 Observed Simultaneously with TESS and XMM-Newton