Flow of gas detected from beyond the filaments to protostellar scales in Barnard 5
Flow of gas detected from beyond the filaments to protostellar scales in Barnard 5
复制标题
在巴纳德 5 号中检测到从细丝到原恒星鳞片的气体流动
DOI：
10.1051/0004-6361/202346357
复制
发表时间：
2023
影响因子：
6.5
通讯作者：
Fuller, G.
中科院分区：
文献类型：
--
作者：
Valdivia-Mena, M.T.;Pineda, J.E.;Segura-Cox, D.M.;Caselli, P.;Schmiedeke, A.;Choudhury, S.;Offner, S.;Neri, R.;Goodman, A.;Fuller, G.
背景来自出生核心外的气体的流入已被证明在主要吸积阶段(0级)之后为原恒星提供了食物。这改变了我们对恒星形成的看法，变成了一幅包括不对称吸积(流光)和环境的更大作用的图景。然而，流光和恒星形成区普遍存在的细丝之间的联系尚不清楚。目的我们研究了Barnard 5(B5)内物质向细丝的流动以及从包层到嵌入的原恒星B5-IRS1的原星盘。我们的目标是跟踪物质从更大、更密集的核心尺度到原恒星盘尺度的流动。方法我们提供了来自NOEMA和覆盖B5相干区的30米望远镜的新的HC3N线数据，以及ALMA H_2CO和C_(18)O朝向原恒星包层的图。我们将多个高斯分量拟合到直线上，从而分解出它们各自的物理分量。我们研究了HC3N的速度梯度，以确定化学新鲜气体流动的方向。结果在致密的核心尺度上，HC3N跟踪从B5区域向细丝的流入。HC3N的速度梯度与向细丝刺吸积加上沿其流动是一致的。我们在H_2CO排放中发现了约2800个Au流光，它相对于原恒星发生蓝移，并在外盘尺度上沉积气体。在大尺度上最强的速度梯度在小尺度上向流光的位置弯曲，表明两者之间存在联系。结论我们的分析表明，气体可以从致密的核心流向原恒星。这意味着，原恒星可获得的质量并不局限于它的包层，而且在主要吸积阶段之后，它可以接收未经化学处理的气体。
ContextThe infall of gas from outside natal cores has proven to feed protostars after the main accretion phase (Class 0). This changes our view of star formation to a picture that includes asymmetric accretion (streamers), and a larger role of the environment. However, the connection between streamers and the filaments that prevail in star-forming regions is unknown.AimsWe investigate the flow of material toward the filaments within Barnard 5 (B5) and the infall from the envelope to the protostellar disk of the embedded protostar B5-IRS1. Our goal is to follow the flow of material from the larger, dense core scale, to the protostellar disk scale.MethodsWe present new HC3N line data from the NOEMA and 30 m telescopes covering the coherence zone of B5, together with ALMA H2CO and C18O maps toward the protostellar envelope. We fit multiple Gaussian components to the lines so as to decompose their individual physical components. We investigated the HC3N velocity gradients to determine the direction of chemically fresh gas flow. At envelope scales, we used a clustering algorithm to disentangle the different kinematic components within H2CO emission.ResultsAt dense core scales, HC3N traces the infall from the B5 region toward the filaments. HC3N velocity gradients are consistent with accretion toward the filament spines plus flow along them. We found a ~2800 au streamer in H2CO emission, which is blueshifted with respect to the protostar and deposits gas at outer disk scales. The strongest velocity gradients at large scales curve toward the position of the streamer at small scales, suggesting a connection between both flows.ConclusionsOur analysis suggests that the gas can flow from the dense core to the protostar. This implies that the mass available for a protostar is not limited to its envelope, and it can receive chemically unprocessed gas after the main accretion phase.