2020 Fiscal Year Final Research Report
Self-gravitational instability and star formation in filamentary molecular clouds penetrated by magnetic fields
| Project/Area Number |
18K03702
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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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| Review Section |
Basic Section 16010:Astronomy-related
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| Research Institution | Nagasaki University |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2021-03-31
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| Keywords | 星形成 / 星間磁場 / 磁気流体力学 |
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| Outline of Final Research Achievements |
We have theoretically studied the role of magnetic fields in the early stages of the formation of stars such as the Sun. Stars are born in molecular clouds, which are composed mainly of molecular hydrogen gas. Most molecular clouds have an elongated filamentary structure, and a magnetic field penetrates perpendicular to their axis. We investigated the self-gravitational instability of long and thin molecular clouds penetrated by magnetic fields. We found that such a structure splits into several gas clumps regardless of the strength of the magnetic field. In addition, when the magnetic field is weak or there is magnetic diffusion, the central part of the gas clumps contracts and stars are formed. We also discuss the scenario from the formation of such filamentary molecular clouds to the star formation.
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| Free Research Field |
天文学
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| Academic Significance and Societal Importance of the Research Achievements |
分子雲は細長いフィラメント形状をしており，そのフィラメントの軸に対して磁場が垂直に貫いていることが観測から知られている．よって，そのような分子雲の分裂から星形成にいたる過程を理論的に明らかにすることは，太陽のような星の誕生過程を理解する上で重要である．本研究結果から，磁場に貫かれた細長い分子雲は，初期の平衡状態や，磁場の強さに関わらず，分子雲コアに分裂する蓋然性が高まった．特に，強い磁場を持つ分子雲コアが，自然に短い時間で形成されることがわかった．太陽のような連星でない単独星の形成には分子雲コアが強い磁場を持つ必要性が指摘されている．今後は，理論の結果と観測との整合性の検証が重要と考える．
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