Lithium Abundance Of The Solar-Type Superflare Stars

We performed the high dispersion spectroscopy of solar-type superflare stars with Subaru/HDS, and estimated the stellar parameters and lithium abundance of the stars to compare them with those of the Sun [1]. Our spectroscopic analysis of superflare stars shows more than half of targets have no evidence of binary system and the stellar parameters are in the range of solar-type stars [2, 3]. We also investigate the correlations of lithium abundance with stellar atmospheric parameters, rotational velocity, and superflare activities to understand the nature of superflare stars and the possibility of the nucleosynthesis of lithium by superflares. The derived lithium abundance in superflare stars does not show the correlation with stellar parameters. As compared with the lithium abundance in Hyades cluster which is younger than the sun, it is suggested that half of the observed stars are young. However, some objects have the low lithium abundances and slowly rotate on the basis of the estimated v sin i and period of brightness variation. These results indicate that the superflare stars are not only young stars but also old stars like our Sun. In our observations, we could not find the any evidence of lithium productions by superflare.