Towards understanding the role of magnetic field in star formation and circumstellar region of evolved star
| Project/Area Number |
17K05388
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Astronomy
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| Research Institution | Kagoshima University |
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Principal Investigator |
Shinnaga Hiroko 鹿児島大学, 理工学域理学系, 准教授 (20709589)
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| Project Period (FY) |
2017-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000)
Fiscal Year 2020: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2017: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | 星間物理 / 星周物理 / 星の進化 / 星形成 / 晩期型星 / メーザー現象 / 質量放出 / 星間磁場 / 星周磁場 / 質量降着 / 偏波観測 / 電波天文学 / 晩期型星星周領域 / 分光観測 / 連続波観測 / 赤外線観測 / 星間物理学 / 宇宙メーザー / 晩期型星の磁気活動 / 天文学 / 天体物理学 / 大質量星 |
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| Outline of Final Research Achievements |
Magnetic field is critical in star formation processes and the evolved star phase. To understand the details of the role of magnetic field, (1) we investigated a star-forming region as an example of an isolated dense core forming a protostar. Using millimeter/submillimeter bands polarimetry, we detected the magnetic field being twisted during gravitational collapse, indicating that the magnetic field plays a pivotal role in the process. (2) In an evolved phase of a massive star (25Msun) just before a supernova explosion, we successfully detected intense magnetic field, 100G and above, in the inner-circumstellar region (<80 R*) using Zeeman splitting method where SiO molecules are abundant. The result revolutionized our understanding of a massive evolved star that is magnetically active, strongly affecting the circumstellar environment. That resulted in environment SiO transitions that are usually thermally excited, i.e., in v=0 state, showing maser action with high polarization.
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| Academic Significance and Societal Importance of the Research Achievements |
高密度分子雲コアの大局的磁場の方向が、原始星を含むコア領域で垂直に折れ曲がり、巻き込まれている最初の例となった。この結果を理論研究と比較し、磁場は原始星の誕生に重要な役割を果たしていることを示した。本成果の記者会見では多くのマスコミにより取り上げられ、星の誕生に磁場が重要であることを社会に広く認識していただく機会となった。赤色超巨星の星周領域での非常に強い磁場強度の発見については、理論的な観点から検証される必要がある。今後は、強い磁場が星間・星周物理過程に与える影響について、具体的な観測例を増やし、強い磁場強度を持つ赤色超巨星は一般的なのか、特殊な例であるのかを見極めていく。
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Report
(7 results)
Research Products
(65 results)
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[Journal Article] The JCMT BISTRO-2 Survey: Magnetic Fields of the Massive DR21 Filament2022
Author(s)
Ching, Tao-Chung; Qiu, Keping; Li, Di; Ren, Zhiyuan; Lai, Shih-Ping; Berry, David; Pattle, Kate; Furuya, Ray; Ward-Thompson, Derek; Johnstone, Doug; Hiroyuki Nakanishi et al.
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Journal Title
The Astrophysical Journal
Volume: 941
Issue: 2
Pages: 122-122
DOI
Related Report
Peer Reviewed / Open Access / Int'l Joint Research
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[Journal Article] Does the magnetic field suppress fragmentation in massive dense cores?2021
Author(s)
Palau, Aina; Zhang, Qizhou; Girart, Josep M.; Liu, Junhao; Rao, Ram; Koch, Patrick M.; Estalella, Robert; Chen, Huei-Ru Vivien; Liu, Hauyu Baobab; Qiu, Keping; Li, Zhi-Yun; Zapata, Luis A.; Bontemps, Sylvain; Ching, Tao-Chung; Shinnaga, Hiroko; Ho, Paul T. P.; Ahmadi, Aida; Beuther, Henrik
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Journal Title
The Astrophysical Journal
Volume: 912
Pages: 159-159
Related Report
Peer Reviewed / Int'l Joint Research
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[Presentation] Dynamic Mass Outflow and Circumstellar Magnetic Field of A Red Supergiant2020
Author(s)
Shinnaga H., Claussen, M.J., Imai, H., Oyadomari, M., Suzuki, T., Richards, A., Grey, M., Etoka, S., Yamamoto, S., Shimojo, M., Murakawa, K.
Organizer
IAU Symposium 360 Astronomical Polarimetry 2020
Related Report
Int'l Joint Research
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