Magnetic fields and massive star formation

Journal Article · Wed Sep 10 04:00:00 EDT 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/792/2/116· OSTI ID:22365100

Zhang, Qizhou; Keto, Eric; Ho, Paul T. P.; Ching, Tao-Chung; Chen, How-Huan ^[1]; Qiu, Keping ^[2]; Girart, Josep M.; Juárez, Carmen ^[3]; Liu, Hauyu; Tang, Ya-Wen; Koch, Patrick M.; Rao, Ramprasad; Lai, Shih-Ping ^[4]; Li, Zhi-Yun ^[5]; Frau, Pau ^[6]; Li, Hua-Bai ^[7]; Padovani, Marco ^[8]; Bontemps, Sylvain ^[9]; Csengeri, Timea ^[10]

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1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
2. School of Astronomy and Space Science, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)
3. Institut de Ciències de l'Espai, (CSIC-IEEC), Campus UAB, Facultat de Ciències, C5p 2, E-08193 Bellaterra, Catalonia (Spain)
4. Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 106, Taiwan (China)
5. Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States)
6. Observatorio Astronómico Nacional, Alfonso XII, 3 E-28014 Madrid (Spain)
7. Department of Physics, The Chinese University of Hong Kong, Hong Kong (China)
8. Laboratoire de Radioastronomie Millimétrique, UMR 8112 du CNRS, École Normale Supérieure et Observatoire de Paris, 24 rue Lhomond, F-75231 Paris Cedex 05 (France)
9. OASU/LAB-UMR5804, CNRS, Université Bordeaux 1, F-33270 Floirac (France)
10. Max Planck Institute for Radioastronomy, Auf dem Hügel 69, D-53121 Bonn (Germany)

Massive stars (M > 8 M {sub ☉}) typically form in parsec-scale molecular clumps that collapse and fragment, leading to the birth of a cluster of stellar objects. We investigate the role of magnetic fields in this process through dust polarization at 870 μm obtained with the Submillimeter Array (SMA). The SMA observations reveal polarization at scales of ≲0.1 pc. The polarization pattern in these objects ranges from ordered hour-glass configurations to more chaotic distributions. By comparing the SMA data with the single dish data at parsec scales, we found that magnetic fields at dense core scales are either aligned within 40° of or perpendicular to the parsec-scale magnetic fields. This finding indicates that magnetic fields play an important role during the collapse and fragmentation of massive molecular clumps and the formation of dense cores. We further compare magnetic fields in dense cores with the major axis of molecular outflows. Despite a limited number of outflows, we found that the outflow axis appears to be randomly oriented with respect to the magnetic field in the core. This result suggests that at the scale of accretion disks (≲ 10{sup 3} AU), angular momentum and dynamic interactions possibly due to close binary or multiple systems dominate over magnetic fields. With this unprecedentedly large sample of massive clumps, we argue on a statistical basis that magnetic fields play an important role during the formation of dense cores at spatial scales of 0.01-0.1 pc in the context of massive star and cluster star formation.

• OSTI ID: 22365100
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 792; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCRETION DISKS
ANGULAR MOMENTUM
CHAOS THEORY
DISTRIBUTION
DUSTS
FRAGMENTATION
GLASS
MAGNETIC FIELDS
POLARIZATION
RANDOMNESS
STAR CLUSTERS
STAR EVOLUTION
STARS