The impact of non-ideal magnetohydrodynamic processes on discs, outflows, counter-rotation and magnetic walls during the early stages of star formation
James Wurster, Matthew R. Bate, Ian A. Bonnell
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19 pages, 13 figures. Accepted for publication in MNRAS
Non-ideal magnetohydrodynamic (MHD) processes -- namely Ohmic resistivity, ambipolar diffusion and the Hall effect -- modify the early stages of the star formation process and the surrounding environment. Collectively, they have been shown to promote disc formation and promote or hinder outflows. But which non-ideal process has the greatest impact? Using three-dimensional smoothed particle radiation non-ideal MHD simulations, we model the gravitational collapse of a rotating, magnetised cloud through the first hydrostatic core phase to shortly after the formation of the stellar core. We investigate the impact of each process individually and collectively. Including any non-ideal process decreases the maximum magnetic field strength by at least an order of magnitude during the first core phase compared to using ideal MHD, and promotes the formation of a magnetic wall. When the magnetic field and rotation vectors are anti-aligned and the Hall effect is included, rotationally supported discs of $r \gtrsim 20$~au form; when only the Hall effect is included and the vectors are aligned, a counter-rotating pseudo-disc forms that is not rotationally supported. Rotationally supported discs of $r \lesssim 4$~au form if only Ohmic resistivity or ambipolar diffusion are included. The Hall effect suppresses first core outflows when the vectors are anti-aligned and suppresses stellar core outflows independent of alignment. Ohmic resistivity and ambipolar diffusion each promote first core outflows and delay the launching of stellar core outflows. Although each non-ideal process influences star formation, these results suggest that the Hall effect has the greatest influence.
Direct evidence for magnetohydrodynamic disk winds driving rotating outflows in protostar HOPS 358
Seoul National University（首尔大学）；SNU Astronomy Research Center, Seoul National University（首尔大学天文研究中心）；NRC Herzberg Astronomy and Astrophysics（NRCA Herzberg天体物理学与天文学研究所）；University of Victoria（维多利亚大学）；Peking University（北京大学）；Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学柯尔夫天体物理与天文学研究所）；Academia Sinica（中央研究院）；Institute of Astronomy and Astrophysics, Academia Sinica（中央研究院天文及天体物理研究所）；Leiden University（莱顿大学）；Leiden Observatory, Leiden University（莱顿大学莱顿天文台）；National Radio Astronomy Observatory（美国国家射电天文台）
Formation of protostars and the launching of stellar core outflows with moving-mesh radiation non-ideal magnetohydrodynamics
Max-Planck-Institut für Astrophysik（马克斯·普朗克天体物理研究所）；Excellence Cluster ORIGINS（ORIGINS 卓越集群）；Center for Astrophysics | Harvard & Smithsonian（哈佛与史密森尼天体物理中心）；Max-Planck-Institut für Extraterrestrische Physik（马克斯·普朗克地外物理研究所）
Protostellar Outflows at the EarliesT Stages (POETS). IX. Magnetohydrodynamic disk winds traced by SO and SO$_2$ in luminous protostars
INAF - Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所阿切特里天文台）；Max-Planck-Institut für Astronomie（马克斯·普朗克天文学研究所）；INAF - Osservatorio Astronomico di Cagliari（意大利国家天体物理研究所卡利亚里天文台）；UK Astronomy Technology Centre, Royal Observatory Edinburgh（英国天文学技术中心爱丁堡皇家天文台）；Faculty of Physics, University of Duisburg-Essen（杜伊斯堡-埃森大学物理学院）；I. Physikalisches Institut, Universität zu Köln（科隆大学第一物理研究所）；Universidad Nacional Autónoma de México, Instituto de Radioastronomía y Astrofísica（墨西哥国立自治大学无线电天文学与天体物理研究所）；Department of Physics and Astronomy, McMaster University（麦克马斯特大学物理与天文学系）
Disc formation and fragmentation using radiative non-ideal magnetohydrodynamics
我们调查的形成和破碎的光盘使用一套三维平滑粒子辐射磁流体动力学模拟。我们的模型被初始化为1 M $_\odot$旋转Bonnor-Ebert球线程与均匀的磁场。我们研究的效果，包括理想和非理想的磁场，方向和强度的磁场，和初始旋转速率。我们遵循的引力坍缩和早期演化的每个系统，直到最终分类的原恒星盘可以确定。在我们的105个模型中，41个碎片，21个形成螺旋结构但不碎片，另外12个形成光滑盘。当初始旋转速率较快且磁场较弱时，更容易发生碎裂。对于更强的磁场强度，包括非理想的MHD促进磁盘的形成，其中几个模型的碎片，而他们的理想MHD同行没有。对于碎片化的模型，我们的参数与碎片化发生的地点或时间之间没有相关性。双极流出仅在17个型号中发射，这些型号具有最初平行于旋转轴的强磁场。反向旋转的信封形式在四个缓慢旋转，强场模型-包括一个理想的MHD模型-表明它们只形成在一小部分的参数空间调查。
Conditions for justifying single-fluid approximation for charged and neutral dust fluids and a smoothed particle magnetohydrodynamics method for dust-gas mixture
Disk Wind Feedback from High-mass Protostars. V. Application of Multi-Modal Machine Learning to Characterize Outflow Properties
Canadian Institute for Theoretical Astrophysics, University of Toronto（加拿大理论天体物理研究所，多伦多大学）；Department of Astronomy, University of Virginia（弗吉尼亚大学天文学系）；Department of Astronomy, Columbia University（哥伦比亚大学天文学系）；Department of Astronomy, University of Wisconsin-Madison（威斯康星大学麦迪逊分校天文学系）；Department of Statistical Sciences, University of Toronto（多伦多大学统计科学系）；David A. Dunlap Department of Astronomy & Astrophysics, University of Toronto（多伦多大学大卫·A·邓普天文与天体物理系）；Dunlap Institute for Astronomy & Astrophysics, University of Toronto（多伦多大学邓普天文与天体物理研究所）；Data Sciences Institute, University of Toronto（多伦多大学数据科学研究所）；Department of Astronomy, School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院天文学系）；State Key Laboratory of Dark Matter Physics, School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院暗物质物理全国重点实验室）
