Initial Physical Condition of Star Formation: Three Dimensional Magnetic Field Structure

2015 Fiscal Year Final Research Report

• Project/Area Number: 26800111
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Astronomy
• Research Institution: National Astronomical Observatory of Japan
• Principal Investigator: Kandori Ryo 国立天文台, 太陽系外惑星探査プロジェクト室, 研究支援員 (90534636)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: 星形成 / 赤外線天文学 / 偏光 / ダスト

Outline of Final Research Achievements

Magnetic fields are believed to play an important role in controlling the stability and evolution of molecular cloud cores leading to the formation of stars. We measured the magnetic field geometry across cores on the basis of the polarization of stars located background to the cores in the near-infrared wavelengths. The cores in rho Ophiuchi cloud and Pipe nebula as well as Bok globules were mapped using the SIRPOL polarimeter on the IRSF 1.4m telescope in South Africa.
In the rho Ophiuchi cloud, we found gradual differences in magnetic field direction over the surface of six sub-regions (cores), which make a large distorted field geometry covering the cloud. The cluster formation process taking place in this region may be the origin of the field distortion. In the Pipe nebula region and Bok globules, we found 3 out of 20 cores with axisymmetrically curved (hourglass-shaped) magnetic fields, suggesting the distortion of frozen-in magnetic field under the influence of gravity.

Free Research Field

星間物理学