Astrophys. J., 892, 128-128 (2020/April-1)
Distortion of magnetic fields in BHR 71.
KANDORI R., TAMURA M., SAITO M., TOMISAKA K., MATSUMOTO T., TAZAKI R., NAGATA T., KUSAKABE N., NAKAJIMA Y., KWON J., NAGAYAMA T. and TATEMATSU K.
Abstract (from CDS):
The magnetic field structure of a star-forming Bok globule BHR 71 was determined based on near-infrared polarimetric observations of background stars. The magnetic field in BHR 71 was mapped from 25 stars. By using a simple 2D parabolic function, the plane-of-sky magnetic axis of the core was found to be θmag = 125° ± 11°. The plane-of-sky mean magnetic field strength of BHR 71 was found to be Bpos = 8.8-15.0 µG, indicating that the BHR 71 core is magnetically supercritical with λ = 1.44-2.43. Taking into account the effect of thermal/turbulent pressure and the plane-of-sky magnetic field component, the critical mass of BHR 71 was Mcr = 14.5-18.7 M☉, which is consistent with the observed core mass of Mcore ≃ 14.7 M☉. We conclude that BHR 71 is in a condition close to a kinematically critical state, and the magnetic field direction lies close to the plane of sky. Since BHR 71 is a star-forming core, a significantly subcritical condition (i.e., the magnetic field direction deviating from the plane of sky) is unlikely, and collapsed from a condition close to a kinematically critical state. There are two possible scenarios to explain the curved magnetic fields of BHR 71, one is an hourglass-like field structure due to mass accumulation and the other is the Inoue & Fukui mechanism, which proposes the interaction of the core with a shock wave to create curved magnetic fields wrapping around the core.
© 2020. The Author(s). Published by the American Astronomical Society.
Interstellar dust - Interstellar magnetic fields - Infrared astronomy - Starlight polarization - Dense interstellar clouds
View the reference in ADS
To bookmark this query, right click on this link: simbad:2020ApJ...892..128K and select 'bookmark this link' or equivalent in the popup menu