On the correlation between starspot activity and superflares on solar-type stars
Project/Area Number |
17K05400
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Multi-year Fund |
Section | 一般 |
Research Field |
Astronomy
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Research Institution | National Astronomical Observatory of Japan (2018-2019) Kyoto University (2017) |
Principal Investigator |
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Project Period (FY) |
2017-04-01 – 2020-03-31
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Project Status |
Completed (Fiscal Year 2019)
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Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2017: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
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Keywords | 太陽型星 / 黒点 / フレア / 晩期型星 / 恒星黒点 / 光学赤外線天文学 |
Outline of Final Research Achievements |
We studied the occurrence frequency and lifetime of large starspots which can produce "superflares" on solar-type stars by using photometric data by Kepler space telescope and ground-based long-term observations. We found that the size distribution of large starspots on solar-type stars as a function of the area of starspots shows the power-law distribution. Our results suggest that the size distribution of starspots on solar-type stars and that of sunspots lie on the same power-law line. We also analyzed the lifetime of starspots on solar-type stars from the rotational brightness modulations and found that larger starspots tend to have longer lifetime. The lifetime of large starspots on solar-type stars is consistent with that predicted from the lifetime-area relation for sunspots. Our findings imply that both sunspots and larger starspots on solar-type stars are caused by the same physical mechanisms.
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Academic Significance and Societal Importance of the Research Achievements |
本研究で得られた研究結果から、スーパーフレアを起こしうる巨大黒点の発生頻度や寿命を初めて明らかにすることができ、それらが従来の太陽観測から知られていた黒点の発生頻度と面積の関係や、寿命と面積の関係の延長線上にのることが明らかとなった。このことは、スーパーフレアを起こすような巨大黒点と太陽で見られる黒点は、同じメカニズムで生成・発展・消滅することを示唆する。さらに、太陽でもスーパーフレアを起こすような巨大黒点が発生しうることを示唆しており、本研究の結果は太陽でのスーパーフレアに伴う巨大磁気嵐等の地球上の文明社会への影響やそのリスク評価にとっても重要である。
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Report
(4 results)
Research Products
(25 results)
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[Journal Article] Impact of Stellar Superflares on Planetary Habitability2019
Author(s)
Yamashiki Yosuke A.、Maehara Hiroyuki、Airapetian Vladimir、Notsu Yuta、Sato Tatsuhiko、Notsu Shota、Kuroki Ryusuke、Murashima Keiya、Sato Hiroaki、Namekata Kosuke、Sasaki Takanori、Scott Thomas B.、Bando Hina、Nashimoto Subaru、Takagi Fuka、Ling Cassandra、Nogami Daisaku、Shibata Kazunari
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Journal Title
The Astrophysical Journal
Volume: 881
Issue: 2
Pages: 114-114
DOI
Related Report
Peer Reviewed / Int'l Joint Research
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[Journal Article] Lifetimes and Emergence/Decay Rates of Star Spots on Solar-type Stars Estimated by Kepler Data in Comparison with Those of Sunspots2019
Author(s)
Namekata, Kosuke; Maehara, Hiroyuki; Notsu, Yuta; Toriumi, Shin; Hayakawa, Hisashi; Ikuta, Kai; Notsu, Shota; Honda, Satoshi; Nogami, Daisaku; Shibata, Kazunari
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Journal Title
The Astrophysical Journal
Volume: 871
Issue: 2
Pages: 187-187
DOI
Related Report
Peer Reviewed / Open Access / Int'l Joint Research
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[Journal Article] Starspot activity and superflares on solar-type stars2017
Author(s)
Maehara, H., Notsu, Y., Notsu, S., Namekata, K., Honda, S., Ishii, T., T., Nogami, D., and Shibata, K.
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Journal Title
Publications of the Astronomical Society of Japan
Volume: 印刷中
Issue: 3
Pages: 41-41
DOI
Related Report
Peer Reviewed / Acknowledgement Compliant
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[Journal Article] Statistical Studies of Solar White-light Flares and Comparisons with Superflares on Solar-type Stars2017
Author(s)
Namekata, K., Sakaue, T., Watanabe, K., Asai, A., Maehara, H., Notsu, Y., Notsu, S., Honda, S., Ishii, T. T., Ikuta, K., Nogami, D., Shibata, K.
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Journal Title
The Astrophysical Journal
Volume: 851
Issue: 2
Pages: 91-91
DOI
Related Report
Peer Reviewed
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[Presentation] Starspots on late-type stars and their correlation with flare activity2018
Author(s)
Maehara, Hiroyuki; Notsu, Yuta; Namekata, Kousuke; Ikuta, Kai; Notsu, Shota; Honda, Satoshi; Nogami, Daisaku; Shibata, Kazunari
Organizer
20th Cambridge Workshop: Cool Stars, Stellar Systems, and the Sun
Related Report
Int'l Joint Research
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[Book] Extreme Solar Particle Storms The hostile Sun2019
Author(s)
Miyake F., Usoskin I., Poluianov S., Baroni M., Cliver E., Dyer C., Ebihara Y., Feinberg A., Hayakawa H., Jull., Kovaltsov G., Kusano K., Maehara H., Mekhaldi F., Mitsuma Y., Muscheler R., Oinonen M., Sokoloff D., Rozanov E., Sukhodolov T., Wacker L., Wang F., Willis D.
Total Pages
276
Publisher
IOP Publishing
ISBN
9780750322300
Related Report
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