Magnetic activities of solar-type stars and dynamo theory investigated through the observations of superflare stars

• Project/Area Number: 16J00320
• Research Category: Grant-in-Aid for JSPS Fellows
• Allocation Type: Single-year Grants
• Section: 国内
• Research Field: Astronomy
• Research Institution: Kyoto University
• Principal Investigator: 野津 湧太 京都大学, 理学研究科, 特別研究員(DC1)
• Project Period (FY): 2016-04-22 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥3,400,000 (Direct Cost: ¥3,400,000); Fiscal Year 2018: ¥1,100,000 (Direct Cost: ¥1,100,000); Fiscal Year 2017: ¥1,100,000 (Direct Cost: ¥1,100,000); Fiscal Year 2016: ¥1,200,000 (Direct Cost: ¥1,200,000)
• Keywords: スーパーフレア / 太陽型星 / フレア / 黒点 / 分光観測 / 光赤外線天文学 / 太陽物理学 / 恒星物理学

Outline of Annual Research Achievements

本研究は、スーパーフレア(最大級の太陽フレアの10-1000倍ものエネルギーの超巨大フレア)を起こす星の詳細な観測研究により、太陽・恒星の磁気活動の解明を目指している。最終年の2018年度は、特に以下の4点について研究実績が得られた。
(1) 一連の研究の継続として、Gaia Data Release 2 (2018年4月公開)から導出された星半径データを適用し、ケプラー宇宙望遠鏡データから報告してきた太陽型星スーパーフレアと巨大黒点の統計的結果の再検討を実施した。これにより、準巨星等の混入を取り除き、太陽のように自転の遅い星でのスーパーフレア発生可能性について、より高い精度で検討を行うことができた(査読論文出版決定済)。また、ケプラーデータを用いた巨大黒点の寿命や生成消滅率に関する共著査読論文も出版された。
(2) 昨年度からの継続で、Apache Point Observatory(APO)3.5m 望遠鏡を用いた、スーパーフレア星の高分散分光観測の結果をまとめ、スーパーフレア星の巨大黒点の存在や自転速度について、Kepler の結果の正しさを確認した(査読論文出版決定済)。
(3)ケプラーの後継機TESS衛星(2018年4月18日打上) で観測される近傍のスーパーフレア星について、APO3.5m望遠鏡での高分散分光観測プロジェクトを昨年度からの継続で実施し、TESSの測光観測や今後の複数回の分光観測と合わせて長期的な変化も探るのに必要なデータを取得した。
(4) 上記(3)に関連し、明るいスーパーフレア星(まずは観測が容易な低温のM型星)に対して、TESS衛星(可視測光)・APO3.5m&0.5m望遠鏡(地上可視分光/測光)・NICER(X線分光)を用いた同時観測を実施した。スーパーフレア中の恒星大気の時間発展や質量放出に迫るためのデータが取得でき、解析を進めている。

Research Progress Status

平成30年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

平成30年度が最終年度であるため、記入しない。

Research Products

• [Int'l Joint Research] University of Washington/University of Colorado Boulder/NASA Goddard Space Flight Center(米国)
• [Int'l Joint Research] Academy of Sciences of Czech Republic(チェコ)
• [Int'l Joint Research] University of Washington/NASA Goddard Space Flight Center(米国)
• [Int'l Joint Research] University of Washington(米国)
• [Int'l Joint Research] Aarhus University(デンマーク)
• [Journal Article] Do Kepler superflare stars really include slowly-rotating Sun-like stars ? - Results using APO 3.5m telescope spectroscopic observations and Gaia-DR2 data - (2019)
  • Author(s): Yuta Notsu, Hiroyuki Maehara, Satoshi Honda, Suzanne L. Hawley, James R. A. Davenport, Kosuke Namekata, Shota Notsu, Kai Ikuta, Daisaku Nogami, Kazunari Shibata
  • Journal Title: The Astrophysical Journal Volume: 印刷中
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] arcesetc: ARC Echelle Spectrograph Exposure Time Calculator (2019)
  • Author(s): Morris Brett、Dorn-Wallenstein Trevor、Levesque Emily、Sakari Charli、Gies Doug、Lester Katherine、Notsu Yuta、Youngblood Allison、McMillan Russet
  • Journal Title: Journal of Open Source Software Volume: 4 Issue: 34 Pages: 1130-1130
  • DOI: 10.21105/joss.01130
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Lifetimes and Emergence/Decay Rates of Star Spots on Solar-type Stars Estimated by Kepler Data in Comparison with Those of Sunspots (2019)
  • Author(s): Namekata, Kosuke; Maehara, Hiroyuki; Notsu, Yuta; Toriumi, Shin; Hayakawa, Hisashi; Ikuta, Kai; Notsu, Shota; Honda, Satoshi; Nogami, Daisaku; Shibata, Kazunari
  • Journal Title: The Astrophysical Journal Volume: 871 Issue: 2 Pages: 187-187
  • DOI: 10.3847/1538-4357/aaf471
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Time resolved spectroscopic observations of an M-dwarf flare star EV Lac during a flare (2018)
  • Author(s): Honda, Satoshi; Notsu, Yuta; Namekata, Kosuke; Notsu, Shota; Maehara, Hiroyuki; Ikuta, Kai; Nogami, Daisaku; Shibata, Kazunari
  • Journal Title: Publications of the Astronomical Society of Japan Volume: - Issue: 4 Pages: 62-62
  • DOI: 10.1093/pasj/psy055
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Time resolved spectroscopic observations of an M-dwarf flare star EV Lac during a flare (2018)
  • Author(s): Honda, S., Notsu, Y., Namekata, K., Notsu, S., Maehara, H., Ikuta, K., Nogami, D., & Shibata, K.
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 印刷中
  • Peer Reviewed
• [Journal Article] Starspot activity and superflares on solar-type stars (2017)
  • Author(s): Maehara, H., Notsu, Y., Notsu, S., Namekata, K., Honda, S., Ishii, T., T., Nogami, D., and Shibata, K.
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 印刷中 Issue: 3 Pages: 41-41
  • DOI: 10.1093/pasj/psx013
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] Statistical Studies of Solar White-light Flares and Comparisons with Superflares on Solar-type Stars (2017)
  • 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.
  • Journal Title: The Astrophysical Journal Volume: 851 Issue: 2 Pages: 91-91
  • DOI: 10.3847/1538-4357/aa9b34
  • Peer Reviewed
• [Journal Article] 太陽型星のスーパーフレア (2017)
  • Author(s): 野津湧太、柴田一成
  • Journal Title: 日本惑星科学会誌 Volume: 26 Pages: 159-168
  • NAID: 130006340316
  • Open Access
• [Journal Article] 生命誕生と太陽フレア ー新説:生命に必要な環境と材料は太陽フレアでつくられた？ (2017)
  • Author(s): 野津湧太
  • Journal Title: 自然と科学の情報誌 milsil (国立科学博物館発行) Volume: 2017年4巻 Pages: 18-19
• [Journal Article] Spectroscopic observations of active solar-analog stars with high X-ray luminosity, as a proxy of superflare stars (2017)
  • Author(s): Notsu, Y., Honda, S., Maehara, H., Notsu, S., Namekata, K., Nogami, D., and Shibata, K.
  • Journal Title: Publications of the Astronomical Society of Japan Volume: 69 Issue: 1 Pages: 12-12
  • DOI: 10.1093/pasj/psw116
  • Peer Reviewed / Acknowledgement Compliant
• [Journal Article] High dispersion spectroscopy of solar-type superflare stars with Subaru/HDS (2016)
  • Author(s): Notsu, Y., Honda, S., Maehara, H., Notsu, S., Shibayama, T., Nogami, D., & Shibata, K.
  • Journal Title: Proceedings of the IAU Symposium Volume: 320 Issue: S320 Pages: 138-138
  • DOI: 10.1017/s1743921316000430
• [Presentation] Do Kepler superflare stars really include slowly-rotating Sun-like stars? - Results using spectroscopic observations and Gaia-DR2 data - (2019)
  • Author(s): Yuta Notsu
  • Organizer: Flux Emergence Workshop 2019
  • Int'l Joint Research
• [Presentation] Do Kepler superflare stars really include slowly-rotating Sun-like stars ? - Latest results using spectroscopic data and Gaia-DR2 stellar radius data - (2019)
  • Author(s): 野津湧太
  • Organizer: 2019年太陽研連シンポジウム
  • Invited
• [Presentation] Do Kepler superflare stars really include slowly-rotating Sun-like stars ? - Results using Gaia-DR2 stellar radius data - (2019)
  • Author(s): 野津湧太(京都大学), 前原裕之(国立天文台), 本田敏志(兵庫県立大学), Suzanne Hawley, James Davenport (University of Washington), 行方宏介, 幾田佳, 野津翔太, 野上大作, 柴田一成(京都大学)
  • Organizer: 日本天文学会2019年春季年会N08a
• [Presentation] Superflares on solar-type stars (2018)
  • Author(s): Yuta Notsu
  • Organizer: European Week of Astronomy and Space Science (EWASS2018), SS12: Flares in the lower atmosphere of the Sun and stars
  • Int'l Joint Research / Invited
• [Presentation] Spectroscopic observations of Kepler/TESS (young) solar-type superflare stars (2018)
  • Author(s): Yuta Notsu
  • Organizer: Environments of Terrestrial Planets Under the Young Sun: Seeds of Biomolecules
  • Int'l Joint Research
• [Presentation] Superflare and starspot activity of solar-type stars studied from photometric and spectroscopic data (2018)
  • Author(s): Yuta Notsu
  • Organizer: JpGU2018 PEN12-07 ("Space Weather, Space Climate, and VarSITI")
  • Int'l Joint Research / Invited
• [Presentation] Spectroscopic observations of Kepler/TESS solar-type superflare stars (2018)
  • Author(s): Yuta Notsu
  • Organizer: Coolstars 20
  • Int'l Joint Research
• [Presentation] Superflares on solar-type stars (recent and future studies) (2018)
  • Author(s): Yuta Notsu
  • Organizer: 2018年度 東京工業大学 惑星・衛星系研究会
• [Presentation] 巨大黒点を持つ近傍太陽型星のK2ミッション測光観測と同時高分散分光観測 (2018)
  • Author(s): 野津湧太・前原裕之・行方宏介・幾田佳・野津翔太・野上大作・柴田一成(京都大学)・本田敏志(兵庫県立大学)・Suzanne Hawley ・James Davenport (University of Washington)
  • Organizer: 日本天文学会2018年秋季年会N03a
• [Presentation] (代理講演)恒星フレア影響の評価に向けた、太陽系外惑星データベースExoKyotoの整備 (2018)
  • Author(s): 山敷庸亮, 野津湧太, 前原裕之 (京都大学), 佐藤達彦 (日本原子力研究開発機構), 黒木龍介, 佐藤啓明, 村嶋慶哉, 野津翔太, 佐々木貴教, 坂東日菜, 梨元昴, 高木風香, 野上大作, 柴田一成 (京都大学), 他 ExoKyoto 開発チーム
  • Organizer: 日本天文学会2018年秋季年会P313a
• [Presentation] 太陽型星のスーパーフレア: これまでの研究と今後の展開 (2018)
  • Author(s): 野津湧太
  • Organizer: AP(天体物理学)ゼミ
• [Presentation] Superflares on solar-type stars (2018)
  • Author(s): Yuta Notsu
  • Organizer: OUTAP colloquium
• [Presentation] Recent studies of superflares on solar-type stars using Kepler data and spectroscopic data (2018)
  • Author(s): Yuta Notsu
  • Organizer: NSO (National Solar Observatory) seminar
• [Presentation] Recent study topics of stellar superflares(from Japanese group) (2018)
  • Author(s): Yuta Notsu
  • Organizer: 2nd workshop of ISSI team "Quasi-periodic Pulsations in Stellar Flares: a Tool for Studying the Solar-Stellar Connection" led by Anne-Marie Broomhall (UK)
  • Int'l Joint Research
• [Presentation] 3.8m望遠鏡・KOOLS-IFUを用いた恒星フレア研究 (2018)
  • Author(s): 野津湧太
  • Organizer: KOOLS-IFU研究会
• [Presentation] 太陽型スーパーフレア星の分光観測 (2018)
  • Author(s): 野津湧太
  • Organizer: 太陽研連シンポジウム
• [Presentation] 188cm望遠鏡を用いたスーパーフレア星のモニタ観測 (2018)
  • Author(s): 野津湧太
  • Organizer: ワークショップ「岡山188cm望遠鏡による新たなサイエンスの展開」
• [Presentation] TESSで観測される明るい太陽型スーパーフレア星候補の高分散分光観測 (2018)
  • Author(s): 野津湧太・前原裕之・Suzanne Hawley ・James Davenport・本田敏志・行方宏介・幾田佳・野津翔太・野上大作・柴田一成
  • Organizer: 日本天文学会2018年春季年会
• [Presentation] G, K, M型星でのスーパーフレア (2017)
  • Author(s): 野津湧太, 前原裕之, 行方宏介, 野津翔太, 幾田佳, 本田敏志, 野上大作, 柴田一成
  • Organizer: JpGU-AGU Joint Meeting 2017
  • Place of Presentation: 幕張メッセ
  • Year and Date: 2017-05-20
• [Presentation] Statistical studies of superflares on G-, K-, M- type stars from Kepler data (2017)
  • Author(s): Yuta Notsu; Hiroyuki Maehara; Satoshi Honda; Shota Notsu; Kosuke Namekata; Kai Ikuta; Daisaku Nogami; Kazunari Shibata
  • Organizer: AASTCS 5: Radio Exploration of Planetary Habitability
  • Place of Presentation: Palm Springs, California (USA)
  • Year and Date: 2017-05-07
• [Presentation] 高い磁気活動を示す近傍の太陽型星の高分散分光観測 (2017)
  • Author(s): 野津湧太
  • Organizer: 第22回天体スペクトル研究会
  • Place of Presentation: 仙台市天文台
  • Year and Date: 2017-03-04
• [Presentation] 3.8m 低分散分光や木曽広視野サーベイとスーパーフレア研究 (2017)
  • Author(s): 野津湧太
  • Organizer: 研究会「木曽広視野サーベイと京都3.8m 即時分光によるタイムドメイン天文学の推進」
  • Place of Presentation: 京都大学理学研究科
  • Year and Date: 2017-02-20
• [Presentation] Statistical studies of superflares on G-, K-, M- type stars from Kepler data (2017)
  • Author(s): Yuta Notsu
  • Organizer: AASTCS (AAS Topical Conference) 5: Radio Exploration of Planetary Habitability
  • Int'l Joint Research
• [Presentation] Statistical properties of superflares on solar-type stars with Kepler data (2017)
  • Author(s): Yuta Notsu
  • Organizer: Kepler/K2 Science Conference IV
  • Int'l Joint Research
• [Presentation] Spectroscopic observations of solar-type superflare stars found from Kepler (2017)
  • Author(s): Yuta Notsu
  • Organizer: Kepler/K2 Science Conference IV
  • Int'l Joint Research
• [Presentation] Active stars in the Kepler field of view (2017)
  • Author(s): Yuta Notsu
  • Organizer: 2nd LAMOST-Kepler workshop
  • Int'l Joint Research / Invited
• [Presentation] Superflare studies and new high-dispersion spectrograph of Kyoto University Okayama 3.8m telescope (2017)
  • Author(s): Yuta Notsu
  • Organizer: 10th Workshop on Astronomy with Precise Radial Velocity Measurements - Extra-Solar Planet Search and Asteroseismology -
  • Int'l Joint Research
• [Presentation] Spectroscopic observations of solar-type superflare stars (2017)
  • Author(s): Yuta Notsu
  • Organizer: The 4th Asia-Pacific Solar Physics Meeting (APSPM2017)
  • Int'l Joint Research
• [Presentation] G, K, M型星でのスーパーフレア (2017)
  • Author(s): 野津湧太
  • Organizer: JpGU-AGU Joint Meeting 2017; PPS07-22 (セッション:「P-PS07 惑星科学」)
• [Presentation] 活動的な近傍太陽型星の高分散分光観測と今後の計画 (2017)
  • Author(s): 野津湧太
  • Organizer: 2017年度岡山（光赤外）ユーザーズミーティング
• [Presentation] Spectroscopic observations of solar-type superflare stars found from Kepler short (1-min) time cadence data (2017)
  • Author(s): 野津湧太・Suzanne Hawley ・前原裕之・本田敏志・野津翔太・行方宏介・幾田佳・野上大作・柴田一成
  • Organizer: 日本天文学会2017年秋季年会
• [Presentation] 太陽型星スーパーフレアの観測的研究と今後の展望 (2017)
  • Author(s): 野津湧太
  • Organizer: 茨城大学重点研究 研究会「突発・変動天体の多波長連携観測」
  • Place of Presentation: 茨城大学
  • Invited
• [Presentation] 高い磁気活動を示す近傍の太陽型星のコロナ温度とEmission Measure の探査、 及びスーパーフレア星との比較 (2016)
  • Author(s): 野津湧太, 前原裕之, 本田敏志, 野津翔太, 行方宏介, 幾田佳, 野上大作, 柴田一成
  • Organizer: 日本天文学会2016 年秋季年会
  • Place of Presentation: 愛媛大学
  • Year and Date: 2016-09-14
• [Presentation] 「3.8m 望遠鏡＋可視高分散分光」で挑むスーパーフレア研究 (2016)
  • Author(s): 野津湧太
  • Organizer: 2016 年度岡山ユーザーズミーティング
  • Place of Presentation: 国立天文台三鷹
  • Year and Date: 2016-09-07
• [Presentation] Statistical properties of superflares on solar-type stars with Kepler data (2016)
  • Author(s): Yuta Notsu
  • Organizer: Hinode-10 Science Meeting
  • Place of Presentation: 名古屋大学
  • Year and Date: 2016-09-05
  • Int'l Joint Research
• [Presentation] High dispersion spectroscopy of solar-type superflare stars with Subaru/HDS (2016)
  • Author(s): Yuta Notsu
  • Organizer: Hinode-10 Science Meeting
  • Place of Presentation: 名古屋大学
  • Year and Date: 2016-09-05
  • Int'l Joint Research
• [Presentation] 高分散分光によるスーパーフレア研究 (2016)
  • Author(s): 野津湧太, 野上大作
  • Organizer: ワークショップ「京大岡山3.8m 望遠鏡時代における可視高分散分光天文学」
  • Place of Presentation: 国立天文台三鷹
  • Year and Date: 2016-07-12
• [Presentation] Superflares on solar-type stars found from Kepler data (2016)
  • Author(s): Yuta Notsu
  • Organizer: Coolstars 19 (The 19th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun
  • Place of Presentation: Uppsala, Sweden
  • Year and Date: 2016-06-06
  • Int'l Joint Research
• [Presentation] Statistical properties of superflares on solar-type stars with Kepler data (2016)
  • Author(s): Yuta Notsu
  • Organizer: Coolstars 19 (The 19th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun)
  • Place of Presentation: Uppsala, Sweden
  • Year and Date: 2016-06-06
  • Int'l Joint Research
• [Presentation] High dispersion spectroscopy of solar-type superflare stars with Subaru/HDS (2016)
  • Author(s): Yuta Notsu
  • Organizer: Coolstars 19 (The 19th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun)
  • Place of Presentation: Uppsala, Sweden
  • Year and Date: 2016-06-06
  • Int'l Joint Research
• [Presentation] Recent studies of superflares on solar-type stars with Kepler data and Subaru/HDS (2016)
  • Author(s): Yuta Notsu
  • Organizer: Seminar at Department of Astoronomy, University of Washington
  • Place of Presentation: University of Washington (Seattle, USA)
• [Presentation] 3.8m 望遠鏡高分散分光器でのスーパーフレア研究計画 (2016)
  • Author(s): 野津湧太
  • Organizer: ワークショップ「京大岡山3.8m 望遠鏡時代における可視高分散分光天文学 II」
  • Place of Presentation: 京都大学理学研究科セミナーハウス
• [Presentation] Recent studies of superflares on solar-type stars with Kepler data and Subaru/HDS (2016)
  • Author(s): Yuta Notsu
  • Organizer: SAC Seminar, Stellar Astrophysics Centre at Aarhus University
  • Place of Presentation: Stellar Astrophysics Centre at Aarhus University (Aarhus, Denmark)
• [Remarks] Webpage of Yuta Notsu
  • URL: https://sites.google.com/colorado.edu/yutanotsu/
• [Remarks] 京都大学3.8m望遠鏡のサイエンス 太陽型星のスーパーフレア
  • URL: http://www.kusastro.kyoto-u.ac.jp/psmt/science.html
• [Remarks] Yuta Notsu's Homepage
  • URL: http://www.kwasan.kyoto-u.ac.jp/~ynotsu/