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Enigma of depressed dipole modes of oscillations in red giants - investigation based on the asymptotic theory

Research Project

Project/Area Number 18K03695
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeMulti-year Fund
Section一般
Review Section Basic Section 16010:Astronomy-related
Research InstitutionThe University of Tokyo

Principal Investigator

Takata Masao  東京大学, 大学院理学系研究科(理学部), 助教 (20334245)

Project Period (FY) 2018-04-01 – 2024-03-31
Project Status Completed (Fiscal Year 2023)
Budget Amount *help
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2019: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Keywords星震学 / 恒星振動 / 恒星磁場 / 恒星自転 / 赤色巨星 / 主系列星
Outline of Final Research Achievements

The purpose of this project is to study the origin of depressed dipole modes, which are found in a part of red giant stars observed by the Kepler spacecraft. The major outputs of the project can be summarised by the following 4 points: (1) detailed theoretical analysis of a hypothesis based on the magnetic field has revealed a problem; (2) by developing the asymptotic theory of red-giant oscillations, we have succeeded in providing physical explanation of the fine structure of the oscillation spectrum; (3) we have derived a formula to describe oscillation frequencies of general stars, taking account of the case of discontinuities in the chemical composition profiles; (4) we have examined the possibility of detecting the internal magnetic field in the main-sequence stars, which are ancestors of red giants, and discovered a candidate star.

Academic Significance and Societal Importance of the Research Achievements

本研究の成果は、直接的には、赤色巨星の星震学を通じてその中心部の構造について新たな知見を得たことであるが、これは単に赤色巨星のみならず、一般の恒星の理論にとっても意義のある結果である。とりわけ内部の磁場構造についての理解は乏しいのが現状なので、本研究のように現実の星について観測に基づく内部磁場の研究は貴重である。また恒星の内部構造と進化の描像は宇宙を理解する上で基盤をなすものであるから、天文学の他分野の研究にも影響するものである。
一方で天文学の研究は、研究者以外の一般社会の多くの人々にとっても興味のある問題であり、本研究もそうした人々の知的好奇心を刺激するという意義を持つ。

Report

(7 results)
  • 2023 Annual Research Report   Final Research Report ( PDF )
  • 2022 Research-status Report
  • 2021 Research-status Report
  • 2020 Research-status Report
  • 2019 Research-status Report
  • 2018 Research-status Report
  • Research Products

    (31 results)

All 2023 2022 2020 2019 2018 Other

All Int'l Joint Research (12 results) Journal Article (8 results) (of which Int'l Joint Research: 6 results,  Peer Reviewed: 7 results,  Open Access: 5 results) Presentation (11 results) (of which Int'l Joint Research: 7 results,  Invited: 3 results)

  • [Int'l Joint Research] Tata Institute of Fundamental Research/Intel Labs(インド)

    • Related Report
      2023 Annual Research Report
  • [Int'l Joint Research] リエージュ大学(ベルギー)

    • Related Report
      2021 Research-status Report
  • [Int'l Joint Research] パリ天文台(フランス)

    • Related Report
      2021 Research-status Report
  • [Int'l Joint Research] Paris Observatory/Universite de Toulouse(フランス)

    • Related Report
      2020 Research-status Report
  • [Int'l Joint Research] University of Liege(ベルギー)

    • Related Report
      2020 Research-status Report
  • [Int'l Joint Research] Technical University of Denmark/Aarhus University(デンマーク)

    • Related Report
      2020 Research-status Report
  • [Int'l Joint Research] Universite de Geneve(スイス)

    • Related Report
      2020 Research-status Report
  • [Int'l Joint Research] Paris Observatory/Universite de Toulouse(フランス)

    • Related Report
      2019 Research-status Report
  • [Int'l Joint Research] University of Liege(ベルギー)

    • Related Report
      2019 Research-status Report
  • [Int'l Joint Research] Aarhus University(デンマーク)

    • Related Report
      2019 Research-status Report
  • [Int'l Joint Research] Paris Observatory(フランス)

    • Related Report
      2018 Research-status Report
  • [Int'l Joint Research] University of Liege(ベルギー)

    • Related Report
      2018 Research-status Report
  • [Journal Article] Inferring Coupling Strengths of Mixed-mode Oscillations in Red Giant Stars Using Deep Learning2023

    • Author(s)
      Dhanpal, Siddharth; Benomar, Othman; Hanasoge, Shravan; Takata, Masao; Panda, Subrata Kumar; Kundu, Abhisek
    • Journal Title

      The Astrophysical Journal

      Volume: 958 Issue: 1 Pages: 63-63

    • DOI

      10.3847/1538-4357/ad0046

    • Related Report
      2023 Annual Research Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Asteroseismology of the dip structure in period-spacings of rapidly rotating γ Doradus stars caused by the coupling between core and envelope oscillations2022

    • Author(s)
      Tokuno, Takato ; Takata, Masao
    • Journal Title

      Monthly Notices of the Royal Astronomical Society

      Volume: 514 Issue: 3 Pages: 4140-4159

    • DOI

      10.1093/mnras/stac1492

    • Related Report
      2022 Research-status Report
    • Peer Reviewed
  • [Journal Article] Multi-cavity gravito-acoustic oscillation modes in stars. A general analytical resonance condition2022

    • Author(s)
      C. Pincon, M. Takata
    • Journal Title

      Astronomy and Astrophysics

      Volume: in press Pages: A139-A139

    • DOI

      10.1051/0004-6361/202243157

    • Related Report
      2021 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Inferring the internal structure of γ Doradus variables from Rossby modes2020

    • Author(s)
      Takata M.、Ouazzani R.-M.、Saio H.、Christophe S.、Ballot J.、Antoci V.、Salmon S. J. A. J.
    • Journal Title

      Astronomy & Astrophysics

      Volume: 644 Pages: A138-A138

    • DOI

      10.1051/0004-6361/202038098

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] First evidence of inertial modes in γ Doradus stars: The core rotation revealed2020

    • Author(s)
      Ouazzani R.-M.、Ligni?res F.、Dupret M.-A.、Salmon S. J. A. J.、Ballot J.、Christophe S.、Takata M.
    • Journal Title

      Astronomy & Astrophysics

      Volume: 640 Pages: A49-A49

    • DOI

      10.1051/0004-6361/201936653

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] A diagnostic diagram for γ Doradus variables and slowly pulsating B-type stars2020

    • Author(s)
      Takata, M.; Ouazzani, R. -M.; Saio, H.; Christophe, S.; Ballot, J.; Antoci, V.; Salmon, S. J. A. J.; Hijikawa, K.
    • Journal Title

      Astronomy & Astrophysics

      Volume: 635 Pages: A106-A106

    • DOI

      10.1051/0004-6361/201936297

    • Related Report
      2019 Research-status Report
    • Peer Reviewed / Open Access / Int'l Joint Research
  • [Journal Article] Evolution of the gravity-offset of mixed modes in RGB stars2019

    • Author(s)
      C. Pincon, M. Takata, B. Mosser
    • Journal Title

      Astronomy & Astrophysics

      Volume: 印刷中

    • Related Report
      2018 Research-status Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Asymptotic view of oscillations of red giant stars2018

    • Author(s)
      Masao Takata
    • Journal Title

      Physics of Oscillating Stars (PHOST), Banyuls-sur-mer, France, 2-7 September 2018

      Volume: -

    • DOI

      10.5281/ZENODO.1874121

    • Related Report
      2018 Research-status Report
    • Open Access
  • [Presentation] Mixed modes2023

    • Author(s)
      Masao Takata
    • Organizer
      PLATO Stellar Science Conference 2023
    • Related Report
      2023 Annual Research Report
    • Int'l Joint Research / Invited
  • [Presentation] Inferring the internal structure of SPB and gamma Dor stars based on a diagnostic diagram2022

    • Author(s)
      Masao Takata
    • Organizer
      TASC6/KASC13 Workshop, Asteroseismology in the Era of Surveys from Space and the Ground: Stars, Planets, and the Milky Way
    • Related Report
      2022 Research-status Report
    • Int'l Joint Research
  • [Presentation] γ Dor型脈動変光星で検出されるロスビー・モードを用いた内部構造診断2020

    • Author(s)
      高田 将郎, R.-M. Ouazzani, 斉尾 英行, S. Christophe, J. Ballot, V. Antoci, S.J.A.J. Salmon
    • Organizer
      日本天文学会2020年秋季年会
    • Related Report
      2020 Research-status Report
  • [Presentation] 赤色巨星の太陽型振動にみられる周波数スペクトルの微細構造の解釈2019

    • Author(s)
      高田将郎
    • Organizer
      日本天文学会2019年秋季年会
    • Related Report
      2019 Research-status Report
  • [Presentation] 星震学の現状と展望(赤色巨星を中心に)2019

    • Author(s)
      髙田 将郎
    • Organizer
      天の川銀河バルジ研究会
    • Related Report
      2018 Research-status Report
    • Invited
  • [Presentation] γ Dor型変光星の内部自転を測る簡便な方法について2019

    • Author(s)
      髙田 将郎
    • Organizer
      日本天文学会2019年春季年会
    • Related Report
      2018 Research-status Report
  • [Presentation] Theoretical analysis of the evolution of the asymptotic parameters of the dipolar mixed modes of red giant stars2018

    • Author(s)
      Masao Takata
    • Organizer
      TASC4/KASC11: First Light in a new Era of Astrophysics
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research
  • [Presentation] Asymptotic view of oscillations of red giant stars2018

    • Author(s)
      Masao Takata
    • Organizer
      Physics of Oscillating Stars, what physics can we learn from oscillating stars?
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research
  • [Presentation] Physics of dipolar mixed modes2018

    • Author(s)
      Masao Takata
    • Organizer
      How much do we trust stellar models? A journey from the observations of stellar pulsations to the physics of stars.
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research / Invited
  • [Presentation] An easy way of estimating internal rotation rates of gamma For stars2018

    • Author(s)
      Masao Takata
    • Organizer
      Workshop on recent topics in helio- and asteroseismology
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research
  • [Presentation] How can we take account of differential rotation in the traditional approximation? --rotation measurement of gamma For stars--2018

    • Author(s)
      Masao Takata
    • Organizer
      Workshop on angular momentum transport in red giants
    • Related Report
      2018 Research-status Report
    • Int'l Joint Research

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Published: 2018-04-23   Modified: 2025-01-30  

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