Theoretical studies on evolution of stellar coronae

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01124
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 16010:Astronomy-related
• Research Institution: Kyoto University
• Principal Investigator: Yokoyama Takaaki 京都大学, 理学研究科, 教授 (00311184)
• Co-Investigator(Kenkyū-buntansha): 堀田 英之 名古屋大学, 宇宙地球環境研究所, 教授 (10767271) ; 草野 完也 名古屋大学, 宇宙地球環境研究所, 教授 (70183796) ; 飯島 陽久 名古屋大学, 宇宙地球環境研究所, 特任助教 (90783952) ; 金子 岳史 新潟大学, 人文社会科学系, 講師 (40838728)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 太陽 / 恒星 / プラズマ / 磁気流体

Outline of Final Research Achievements

Regarding stellar dynamo, we carried out large-scale, high-resolution calculations of the Sun's internal magnetothermal convection under the influence of rotation, and succeeded in reproducing the solar differential rotation, which no one had been able to achieve before (Hotta, Kusano). We conducted, for the first time, large-scale calculations to solve coronal heating and solar wind acceleration in a physically consistent manner from the solar surface to 30 solar radii (Iijima, Hotta et al.). Through high-resolution calculations, we showed that the formation of a magnetic tornado structure increases the magnetic energy transport in the solar atmosphere by several times, and succeeded in heating the stellar coronal loop (Kuniyoshi, Yokoyama, Iijima et al.). We conducted a large-scale parametric survey of sunspot formation and clarified the relationship between the solar internal downdraft and surface magnetic energy accumulation (Kaneko, Hotta, Toriumi, Kusano et al.).

Free Research Field

天文学

Academic Significance and Societal Importance of the Research Achievements

本研究成果の学術的意義は、星コロナの磁気ループ描像を、物理的整合性がある第一原理計算に基づく統合モデルとして発展させたことにある。星の差動回転、星コロナ形成について、ad hocな仮定を最小にとどめた大規模数値計算を実行することで、小質量星とその惑星環境のX線紫外線環境について理論的にロバストなモデルを構築し、恒星進化と惑星系進化の理解に貢献したといえる。