论文标题

磁场方向在致密芯中对原始信封气体运动学的影响

Effects of magnetic field orientations in dense cores on gas kinematics in protostellar envelopes

论文作者

Gupta, Aashish, Yen, Hsi-Wei, Koch, Patrick, Bastien, Pierre, Bourke, Tyler L., Chung, Eun Jung, Hasegawa, Tetsuo, Hull, Charles L. H., Inutsuka, Shu-ichiro, Kwon, Jungmi, Kwon, Woojin, Lai, Shih-Ping, Lee, Chang Won, Lee, Chin-Fei, Pattle, Kate, Qiu, Keping, Tahani, Mehrnoosh, Tamura, Motohide, Ward-Thompson, Derek

论文摘要

从理论上讲,在恒星形成过程中,磁场和旋转轴之间的错位被认为在动态上很重要,但是,这种影响的程度在观察方面仍不清楚。对于Perseus Molecular Cloud中32类0和I Protostar的样本,我们使用C $^{18} $ o SMA Masses调查和磁场结构的数据分析了气体运动,并使用JCMT BISTRO-1调查的850 $ $ M polarimetric数据进行了磁场结构。我们没有发现在c $^{18} $ o中的速度梯度以1,000 AU量表的排放量与在4,000 au量表中的流出和磁场方向之间的不一致,并且在VELOCITION梯度之间也没有相关性的磁场分散剂,并且在磁场之间也没有相关性。但是,在我们通过插入运动将旋转运动归一化后,对未对准角度的显着依赖是出现的,其中比率从$ \ \ lyssim1 $增加到$ \ gtrsim1 $随着不一致角度的增加而增加。这表明,未对准可能会促使角动量传输到包膜量表,但并不是确定包膜旋转的主要因素,而其他参数(例如Protostellar源中的质量增生)也起着重要作用。考虑投影效应后,这些结果仍然有效。我们在原始信封中估计的角动量与已知原始磁盘的大小之间的比较表明,在Protostellar信封中,RADII $ \ sim $ 1,000-100 AU之间可能会损失显着的角动量。

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, 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 C$^{18}$O data from the SMA MASSES survey and the magnetic field structures using 850 $μ$m polarimetric data from the JCMT BISTRO-1 survey and archive. We do not find any significant correlation between the velocity gradients in the C$^{18}$O emission in the protostellar envelopes at a 1,000 au scale and the misalignment between the outflows and magnetic field orientations in the dense cores at a 4,000 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 $\lesssim1$ to $\gtrsim1$ with increasing misalignment angles. 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, like 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 $\sim$1,000-100 au in protostellar envelopes.

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