Li-Ching Huang (NTNU), Chia-Lung Lin (NCU), Wing-Huen Ip (NCU)
K dwarf EPIC210651981 is a frequent flaring star detected with K2 observation. G dwarf binary system KIC 11551430 also with flares, which was detected with Kepler observation. We collect the 3- and 2-night lightcurve and low-resolution spectral data with SLT telescope and LOT telescope with the new spectrometer LISA onboard in Lulin Observatory in October 2020 and April 2021. A superflare event on EPIC210651981 was detected on Oct. 31 2020. H-alpha equivalent width provides the information of the stellar magnetic activity. Later type stars and flare stars show larger H-alpha equivalent width, which means that H alpha emission from the chromosphere activity fills the H-alpha absorption line in the stellar spectra. The spectral data we had analyzed are not taken during the flare event occurring. This spectra series provide the information before, during and after the superflare event, is a powerful tool to compare the magnetic active levels of different flare stages.