BHR 71的磁场畸变
Distortion of Magnetic Fields in BHR 71
摘要：
根据对背景恒星的近红外偏振观测，确定了一个恒星形成的博克球状体BHR 71的磁场结构。BHR 71的磁场由25颗恒星组成。利用一个简单的二维抛物函数，得到了地核的天平面磁轴为$θ_{\rm mag} = 125^{\circ} \pm 11^{\circ}$。发现BHR 71的天平面平均磁场强度为$B_{\rm pos} = 8.8 - 15.0$ $μ$ G，表明BHR 71的核心是磁超临界的$λ= 1.44 - 2.43$。考虑到热/湍流压力和天空磁场分量的影响，BHR 71的临界质量为$M_{\rm cr} = 14.5-18.7$ M $_{\odot}$，这与观测到的$M_{\rm core} \approx 14.7$ M $_{\odot}$的核心质量一致（Yang等人，2017）。我们得出结论，BHR 71是在一个条件接近运动学临界状态，磁场方向位于接近天球平面。由于BHR 71是一个恒星形成核心，一个显着的亚临界条件（即，偏离天空平面的磁场方向），并且从接近运动学临界状态的条件崩溃。BHR 71的弯曲磁场有两种可能的解释，一种是由于质量积累导致的沙漏状场结构，另一种是Inoue \& Fukui（2013）机制，该机制提出了核心与冲击波的相互作用，以产生缠绕核心的弯曲磁场。
英文摘要：
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 $θ_{\rm mag} = 125^{\circ} \pm 11^{\circ}$. The plane-of-sky mean magnetic field strength of BHR 71 was found to be $B_{\rm pos} = 8.8 - 15.0$ $μ$G, 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 $M_{\rm cr} = 14.5-18.7$ M$_{\odot}$, which is consistent with the observed core mass of $M_{\rm core} \approx 14.7$ M$_{\odot}$ (Yang et al. 2017). 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 (2013) mechanism, which proposes the interaction of the core with a shock wave to create curved magnetic fields wrapping around the core.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
