Study of Magnetic Field Structure in Massive Star-forming Regions

2019 Fiscal Year Final Research Report

• Project/Area Number: 16H05730
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 海外学術
• Research Field: Astronomy
• Research Institution: Nagoya City University
• Principal Investigator: Sugitani Koji 名古屋市立大学, 大学院システム自然科学研究科, 教授 (80192615)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 星間磁場 / 大質量星形成 / 分子雲 / 近赤外線偏光観測

Outline of Final Research Achievements

How massive stars are formed is one of the important issues in current astronomy research, however it is not well understood. In particular, it is not clear how the interstellar magnetic field is related to the formation of massive stars in giant molecular clouds. Therefore, the magnetic field structures of giant molecular clouds with massive stars and those without massive stars were investigated by near-infrared polarization observations, in order to examine their magnetic filed structures in comparison with their density structures. As a result, we found that massive stars are formed in the region where the magnetic field is relatively weak with respect to column density, whereas only low- and intermediate-masse stars are formed in the region where the magnetic field is relatively strong. This suggests that the magnetic field controls the mass of the star formed.

Free Research Field

赤外線天文学

Academic Significance and Societal Importance of the Research Achievements

天文衛星「プランク」により全天域でサブミリ波偏光観測で星間磁場が調べられているが、その角分解能は十分でなく巨大分子雲の局所的な磁場構造を調べるのに十分でなかった。より高い角分解で磁場構造を調べることができる近赤外線偏光観測は従来から行われていたが観測範囲が狭く、巨大分子雲の全体を詳細に調べた例はほとんどなかった。本研究では、いくつかの巨大分子雲の全体の磁場構造を近赤外線偏光観測で詳細に調べることにより、星間磁場が星形成に重要な影響を与えていることを観測的に示した。このことは、星形成の研究分野に重要な知見を与えたと考えられる。