AI 中文总结
本研究通过ALMA观测IRAM 04191+1522的分子气体，发现其存在新外流腔及逆时针旋转证据，支持该极暗天体为双星系统，需更高分辨率观测进一步研究其子结构与演化。
AI 中文摘要
多数褐矮星（BDs）的形成机制仍未明确，它们可能在类似低质量恒星形成过程的分子云核中形成，也可能通过原行星盘碎裂产生。研究最年轻、被包埋的源是区分这些形成场景的关键。我们利用存档的ALMA对13CO、C18O和SO的观测数据，研究年轻且被包埋的极暗天体（VeLLO）IRAM 04191+1522周围的分子气体形态与运动学特征，追踪源周围几十到几百天文单位（au）尺度的气体，寻找外流或内落结构。红移和蓝移的13CO（3-2）发射呈现出不同的形态与运动学特征：西北方向的蓝移发射可能追踪到与此前报道的约0.1秒差距（pc）CO外流取向不同的激波物质；主要分布在东南和西南方向的红移发射可能追踪外流腔的基部，该腔的位置角暗示存在第二个外流，支持该VeLLO可能为双星的性质。C18O（2-1）发射结构极为复杂，包含不同空间尺度、与源距离各异的结构，可能混合了分子外流、外流腔和盘的发射。SO 65-54的观测显示中心源周围存在逆时针旋转的证据，同时还有一个来源不明的北部结构。我们已识别出一组复杂的13CO（3-2）和C18O（2-1）结构，以及一个与此前探测到的外流位置角不同的新外流腔的证据，这支持IRAM 04191+1522是双星系统的观点，而北部的SO气体结构仍未得到解释，需要中等尺度的更高光谱分辨率观测来表征这些子结构、它们与更大尺度结构的联系，以及确定该系统的最终演化结果。
英文摘要
The formation of the majority of brown dwarfs (BDs) remains uncertain. They may form in molecular cloud cores in a process akin to low mass star formation, or via fragmentation in circumstellar discs. Studying the youngest, most embedded sources is crucial for distinguishing these scenarios. We investigate molecular gas morphology and kinematics around one young & embedded very low luminosity object (VeLLO), IRAM 04191+1522, utilising archival ALMA observations of 13CO, C18O, and SO. We trace gas on scales of a few 10s to 100s of au around the source to search for outflowing and/or infalling structures. The red and blueshifted 13CO (3-2) emission show distinct morphologies and kinematics. The blueshifted emission to the north-west may trace shocked material oriented differently from the previously reported approx. 0.1 pc CO outflow. Redshifted emission mainly to the south-east and south-west may trace the base of an outflow cavity. The position angle of this cavity suggests the presence of a second outflow, which supports the possible binary nature of this VeLLO. The C18O (2-1) emission is highly complex, comprising structures at different spatial scales and distances from the source. These may trace a mix of molecular outflow, outflow cavity, and disc emission. SO 65-54 reveals evidence for anticlockwise rotation around the central source, together with a northern structure of uncertain origin. We have identified a complex set of 13CO (3-2) and C18O (2-1) structures alongside evidence of a new outflow cavity at a distinct position angle from previously detected outflows. This supports the scenario that IRAM 04191+1522 is a binary system. The northern SO gas structure remains unexplained. Higher spectral resolution observations at intermediate scales are needed to characterise these substructures, their connection to larger scale structures, and to determine this system's final fate.
CommentsAccepted for publication in A&A on 17/08/2026. 21 pages, 15 figures and 5 tables
