2019ApJ...871..203L

We present long-term, multicolor photometric monitoring and spectroscopic observations of the short-period M-type eclipsing binary BX Tri. Six flare events were recorded over four years from 2014 to 2017. Three of them were detected on one night within an orbital cycle. The strongest one was identified on 2014 December 23. With the amplitudes ΔB = 0.48 mag, ΔV = 0.28 mag, ΔR = 0.10 mag, and ΔI = 0.02 mag, the total energy due to the flare event was measured to be 4.08 (±0.24) x 10³⁴ erg, exceeding the superflare level (10³⁴). Based on the observations, the evolutionary status of the binary system and the long-term orbital period changes were analyzed. It reveals that BX Tri is probably a semidetached system with the primary component filling its Roche lobe. The extremely high occurrence of flare events in the binary could be related to rapid mass transfer between the components.