Effects of Magnetic Field Orientations in Dense Cores on Gas Kinematics in Protostellar Envelopes
Effects of Magnetic Field Orientations in Dense Cores on Gas Kinematics in Protostellar Envelopes
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DOI：
10.3847/1538-4357/ac63bc
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发表时间：
2022-04
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通讯作者：
Aashish Gupta;Hsi-Wei Yen;P. Koch;P. Bastien;T. Bourke;E. Chung;T. Hasegawa;C. Hull;S. Inutsuka;J. Kwon;W. Kwon;S. Lai;Chang Won Lee;Chin-Fei Lee;K. Pattle;K. Qiu;M. Tahani;Motohide Tamura;D. Ward-Thompson
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作者：
Aashish Gupta;Hsi-Wei Yen;P. Koch;P. Bastien;T. Bourke;E. Chung;T. Hasegawa;C. Hull;S. Inutsuka;J. Kwon;W. Kwon;S. Lai;Chang Won Lee;Chin-Fei Lee;K. Pattle;K. Qiu;M. Tahani;Motohide Tamura;D. Ward-Thompson
理论上，致密核心中的磁场和旋转轴之间的不对准被认为在星星形成过程中具有重要的动力学意义;然而，这种影响的程度在观测上仍然不清楚。对于英仙座分子云中的32个0类和I类原恒星样本，我们使用SMA MASSES调查的C18 O数据分析了气体运动，并使用JCMT BISTRO-1调查和存档的850 μm偏振数据分析了磁场结构。在1000 Au尺度的原恒星包层中C18 O发射的速度梯度与4000 Au尺度的致密核中流出物和磁场方向之间的不对准之间没有任何显著的相关性，并且速度梯度与磁场的角色散之间也没有相关性。然而，一个显着的依赖于失准角出现后，我们规范化的旋转运动的下落运动，其中的比率增加从0.01到0.01随着失准角的增加。这表明，错位可以促使角动量运输到信封规模，但不是一个决定信封旋转的主导因素，和其他参数，如原恒星源的质量吸积，也发挥了重要作用。这些结果在考虑投影效应后仍然有效。我们估计的角动量在原恒星信封和已知的原恒星盘的大小之间的比较表明，显着的角动量可能会失去半径为1000和100 Au的原恒星信封。
Theoretically, misalignment between the magnetic field and rotational axis in a dense core is considered to be dynamically important in the star formation process; however, the extent of this influence remains observationally unclear. For a sample of 32 Class 0 and I protostars in the Perseus Molecular Cloud, we analyzed gas motions using C18O data from the SMA MASSES survey and the magnetic field structures using 850 μm polarimetric data from the JCMT BISTRO-1 survey and archive. We do not find any significant correlation between the velocity gradients in the C18O emission in the protostellar envelopes at a 1000 au scale and the misalignment between the outflows and magnetic field orientations in the dense cores at a 4000 au scale, and there is also no correlation between the velocity gradients and the angular dispersions of the magnetic fields. However, a significant dependence on the misalignment angles emerges after we normalize the rotational motion by the infalling motion, where the ratios increase from ≲1 to ≳1 with increasing misalignment angle. This suggests that the misalignment could prompt angular momentum transportation to the envelope scale but is not a dominant factor in determining the envelope rotation, and other parameters, such as mass accretion in protostellar sources, also play an important role. These results remain valid after taking into account projection effects. The comparison between our estimated angular momentum in the protostellar envelopes and the sizes of the known protostellar disks suggests that significant angular momentum is likely lost between radii of ∼1000 and 100 au in protostellar envelopes.