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arXiv · 1804.07122

Statistical Study of Solar White-light Flares and Comparison with Superflares on Solar-type Stars

Kosuke Namekata·Takahito Sakaue·Kyoko Watanabe·Ayumi Asai·Hiroyuki Maehara·Yuta Notsu·Shota Notsu·Satoshi Honda·Takako T. Ishii·Kai Ikuta·Daisaku Nogami·Kazunari Shibata
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Abstract

Recently, many superflares on solar-type stars were discovered as white-light flares (WLFs). A correlation between the energies (E) and durations (t) of superflares is derived as $t\propto E^{0.39}$, and this can be theoretically explained by magnetic reconnection ($t\propto E^{1/3}$). In this study, we carried out a statistical research on 50 solar WLFs with SDO/HMI to examine the t-E relation. As a result, the t-E relation on solar WLFs ($t\propto E^{0.38}$) is quite similar stellar superflares, but the durations of stellar superflares are much shorter than those extrapolated from solar WLFs. We present the following two interpretations; (1) in solar flares, the cooling timescale of WL emission may be longer than the reconnection one, and the decay time can be determined by the cooling timescale; (2) the distribution can be understood by applying a scaling law $t\propto E^{1/3}B^{-5/3}$ derived from the magnetic reconnection theory.

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Kosuke Namekata, Takahito Sakaue, Kyoko Watanabe, Ayumi Asai, Hiroyuki Maehara, Yuta Notsu, Shota Notsu, Satoshi Honda, Takako T. Ishii, Kai Ikuta, Daisaku Nogami, Kazunari Shibata. 2018-04-19. Statistical Study of Solar White-light Flares and Comparison with Superflares on Solar-type Stars. https://doi.org/10.1017/s1743921318001126

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