Continuity of accretion from clumps to Class 0 high-mass protostars in SDC335
Continuity of accretion from clumps to Class 0 high-mass protostars in SDC335
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DOI：
10.1051/0004-6361/201936043
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发表时间：
2020-12
影响因子：
6.5
通讯作者：
A. Avison;G. Fuller;N. Peretto;A. Duarte-Cabral;A. Rosen;A. Traficante;J. Pineda;R. Güsten;N. Cunningham
中科院分区：
文献类型：
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作者：
A. Avison;G. Fuller;N. Peretto;A. Duarte-Cabral;A. Rosen;A. Traficante;J. Pineda;R. Güsten;N. Cunningham
上下文红外暗云（IRDC）SDC335.579-0.292（以下简称SDC 335）是一个巨大的恒星形成云，它被发现正在向银河系中最大的星星形成核心之一坍缩。已知SDC 335在演化的早期阶段有三个大质量的原恒星天体，并且存档的阿尔马第0周期数据（分辨率约为5“"）表明，在HNC检测到的区域中存在至少一个分子外流。从大规模的原恒星物体的分子流出的观测使我们能够估计原恒星的吸积率，以及评估恒星在其形成过程中对其纳塔尔云的破坏性影响。目标。这项工作的目的是识别和分析SDC 335内原恒星驱动的分子外流的性质，并利用这些外流来帮助改进该云中年轻大质量原恒星的性质。方法.我们利用来自澳大利亚望远镜SiO和I类CH 3OH脉泽发射紧凑阵列的新数据（分辨率为~3“”），以及阿塔卡马探路者实验和档案阿塔卡马大毫米/亚毫米阵列（阿尔马）CO，13 CO（~1“”）和HNC数据进行的四次CO跃迁观测，对SDC 335中的分子流出进行了成像。我们引入了一个广义的参数来约束流出倾斜角度的基础上观察到的流出属性。然后，我们使用每个流出的属性来推断驱动它们的原恒星源的吸积率。这些吸积性质使我们能够推断出源的演化特征。激波跟踪SiO发射和CH 3OH I类脉泽发射使我们能够定位流出物和物质通过SDC 335的辅助臂落入中心区域之间的相互作用区域。结果我们确定了三个分子流出SDC 335-一个与每个已知的紧凑的H II区域的IRDC。这些外流的速度范围约为10 km s−1，温度约为60 K。两个质量最大的源（相隔约9000 Au）的流出轴在投影中是垂直的。在其中一个流出物的波瓣中检测到一个高度准直的喷流状结构，速度梯度约为155 km s-1 pc-1。流出的性质表明，SDC 335原恒星处于其演化的早期阶段（0级），有可能形成超过50 M的恒星。从外流推断，测量到的原恒星的总吸积速率为1.4（±0.1）× 10−3 M yr−1，这与在秒差距尺度上向云中心的总质量下降速率2.5（±1.0）× 10−3 M yr−1相当，表明物质从云向核心尺度的流动几乎是连续的。最后，我们确定了多个地区的外流相互作用与下落的材料在云的六个附属武器，创造冲击区和泵I类甲醇脉泽发射。这些地区提供了有用的案例研究，为未来的调查的破坏性影响的年轻大质量恒星的纳塔尔云。
Context. The infrared dark cloud (IRDC) SDC335.579-0.292 (hereafter, SDC335) is a massive (~5000 M⊙) star-forming cloud which has been found to be globally collapsing towards one of the most massive star forming cores in the Galaxy, which is located at its centre. SDC335 is known to host three high-mass protostellar objects at early stages of their evolution and archival ALMA Cycle 0 data (at ~5′′ resolution) indicate the presence of at least one molecular outflow in the region detected in HNC. Observations of molecular outflows from massive protostellar objects allow us to estimate the accretion rates of the protostars as well as to assess the disruptive impact that stars have on their natal clouds during their formation. Aims. The aim of this work is to identify and analyse the properties of the protostellar-driven molecular outflows within SDC335 and use these outflows to help refine the properties of the young massive protostars in this cloud. Methods. We imaged the molecular outflows in SDC335 using new data from the Australia Telescope Compact Array of SiO and Class I CH3OH maser emission (at a resolution of ~3′′) alongside observations of four CO transitions made with the Atacama Pathfinder EXperiment and archival Atacama Large Millimeter/submillimeter Array (ALMA) CO, 13CO (~1′′), and HNC data. We introduced a generalised argument to constrain outflow inclination angles based on observed outflow properties. We then used the properties of each outflow to infer the accretion rates on the protostellar sources driving them. These accretion properties allowed us to deduce the evolutionary characteristics of the sources. Shock-tracing SiO emission and CH3OH Class I maser emission allowed us to locate regions of interaction between the outflows and material infalling to the central region via the filamentary arms of SDC335. Results. We identify three molecular outflows in SDC335 – one associated with each of the known compact H II regions in the IRDC. These outflows have velocity ranges of ~10 km s−1 and temperatures of ~60 K. The two most massive sources (separated by ~9000 AU) have outflows with axes which are, in projection, perpendicular. A well-collimated jet-like structure with a velocity gradient of ~155 km s−1 pc−1 is detected in the lobes of one of the outflows. The outflow properties show that the SDC335 protostars are in the early stages (Class 0) of their evolution, with the potential to form stars in excess of 50 M⊙. The measured total accretion rate, inferred from the outflows, onto the protostars is 1.4(±0.1) × 10−3 M⊙ yr−1, which is comparable to the total mass infall rate toward the cloud centre on parsec scales of 2.5(±1.0) × 10−3 M⊙ yr−1, suggesting a near-continuous flow of material from cloud to core scales. Finally, we identify multiple regions where the outflows interact with the infalling material in the cloud’s six filamentary arms, creating shocked regions and pumping Class I methanol maser emission. These regions provide useful case studies for future investigations of the disruptive effect of young massive stars on their natal clouds.