Can Superflares Occur on Our Sun?
Can Superflares Occur on Our Sun? Kazunari Shibata1, Hiroaki Isobe2, Andrew Hillier1, Arnab Rai Choudhuri3,4, Hiroyuki Maehara1,5, Takako T. Ishii1, Takuya Shibayama6, Shota Notsu6, Yuta Notsu6, Takashi Nagao6, Satoshi Honda1,7, and Daisaku Nogami1 1 Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto, 607-8471, Japan 2 Unit of Synergetic Studies for Space, Kyoto University, Yamashina, Kyoto, 607-8471, Japan 3 Department of Physics, Indian Institute of Science, Bangalore, 560012, India 4 National Astronomical Observatory, Mitaka, Tokyo, 181-8588, Japan 5 Kiso Observatory, Institute of Astronomy, School of Science, The University of Tokyo 10762-30, Mitake, Kiso-machi, Kiso-gun, Nagano 397-0101, Japan 6 Department of Astronomy, Faculty of Science, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan 7 Nishi-Harima Astronomical Observatory, Center for Astronomy, University of Hyogo, Sayo, Hyogo 679-5313, Japan Accepted by Publ. Astron. Soc. Japan on Dec. 6, 2012 (to be published on PASJ vol. 65, No. 3, (2013) June 25) 1 Abstract Recent observations of solar type stars with the Kepler satellite by Maehara et al. have revealed the existence of superflares (with energy of 1033 ~ 1035 erg) on Sun-like stars, which are similar to our Sun in their surface temperature (5600 K ~ 6000 K) and slow rotation (rotational period > 10 days). From the statistical analysis of these superflares, it was found that superflares with energy 1034 erg occur once in 800 years and superflares with 1035 erg occur once in 5000 years on Sun-like stars. In this paper, we examine whether superflares with energy of 1033 ~ 1035 erg could occur on the present Sun through the use of simple order-of-magnitude estimates based on current ideas relating to the mechanisms of the solar dynamo.
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