Prominences show a surprising amount of fine structure and it is widely believed that their threads, as seen in H$α$ observations, provide indirect information concerning magnetic field topology. We investigate the spontaneous emergence and evolution of fine structure in high-density condensations formed through the process of thermal instability under typical solar coronal conditions. Our study reveals intricate multidimensional processes that occur through in situ condensations in a representative coronal volume in a low plasma beta regime. We performed 2D and 3D numerical simulations of interacting slow magnetohydrodynamic (MHD) wave modes when all relevant non-adiabatic effects are included.
We show that the interaction of multiple slow MHD wave modes in a regime unstable to the thermal mode leads to thermal instability. This initially forms pancake-like structures almost orthogonal to the local magnetic field, while low-pressure induced inflows of matter generate rebound shocks. This is succeeded by the rapid disruption of these pancake sheets through thin-shell instabilities evolving naturally from minute ram pressure imbalances. This eventually creates high-density blobs accompanied by thread-like features from shear flow effects. The further evolution of the blobs follows the magnetic field lines, such that a dynamical realignment with the background magnetic field appears. However, the emerging thread-like features are not at all field-aligned, implying only a very weak link between fine structure orientation and magnetic field topology which has far-reaching implications for field topology interpretations based on H$α$ observations.
Dense cores and filaments in M16: Enhanced formation efficiency in the stellar feedback-driven shell
National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）；University of Chinese Academy of Sciences（中国科学院大学）；Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM（巴黎萨克雷大学、巴黎西岱大学、法国原子能和替代能源委员会、法国国家科学研究中心、天体物理学与分子星际介质实验室）
The Role of Magnetic Fields in the Stability and Fragmentation of Filamentary Molecular Clouds: Two Case Studies at OMC-3 and OMC-4
我们给出了猎户座A大质量长分子云复合体中两个区域OMC-3和OMC-4的稳定性分析。我们获得了$214~μ$ m HAWC+/SOFIA的偏振数据，并利用档案数据计算了柱密度和C $^{18}$ O（1-0）发射线。我们发现，在这两个观察到的区域和偏振分数是反相关的列密度和偏振角色散函数的去偏振。我们发现OMC-3中的对流云和致密团簇是磁超临界的，具有强次维里性质。这一区域应该处于引力坍缩阶段，并且与该区域形成的许多年轻恒星天体（YSO）相一致。我们的相对取向（HRO）的直方图分析表明，磁场在OMC-3的致密气体结构的动态次主导。给出了OMC-4的第一张偏振图。我们发现，除了一个细长的致密核心，这可能是一个附属结构的投影效应对准接近视线的结果，观察到的区域一般是磁亚临界。相对较大的速度色散和不寻常的积极的形状参数，在高柱密度的HRO分析表明，我们的视角可能接近OMC-4的附属子结构的轴。OMC-4中占主导地位的强磁场不利于恒星形成，并且与OMC-3中的YSO少得多相一致。
Formation of a Protostellar Multiple System via Rotational Fragmentation
State Key Laboratory of Radio Astronomy and Technology, Shanghai Astronomical Observatory, Chinese Academy of Sciences（中国科学院上海天文台射电天文与技术重点实验室）；Department of Astronomy, School of Science, The University of Tokyo（东京大学理学部天文学系）；Center for Astrophysics, Harvard Smithsonian（哈佛史密松天体物理中心）；Departamento de Astronomía, Universidad de Chile（智利大学天文学系）；Chinese Academy of Sciences South America Center for Astronomy, National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台拉美天文中心）
Characterizing the hierarchical structure of filaments I. On the origin of the length-mass (L-M) scaling relation
Hamburger Sternwarte, Universität Hamburg（汉堡天文台，汉堡大学）；I. Physikalisches Institut, Universität zu Köln（第一物理研究所，科隆大学）；Institute for Astrophysics, University of Vienna（天体物理研究所，维也纳大学）
Fragmentation of Dense Rotation-Dominated Structures Fed by Collapsing Gravomagneto-Sheetlets and Origin of Misaligned 100 au-Scale Binaries and Multiple Systems
ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- XII: Fragmentation and multi-scale gas kinematics in protoclusters G12.42+0.50 and G19.88-0.53
ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions $-$ XVII. High-mass star-formation through a large-scale collapse in IRAS 15394$-$5358
