The earliest stages of low-mass star formation are unclear, with the first hydrostatic core (FHSC) as the transition stage between a prestellar and protostellar core. This work describes the local (∼4000 au) outflow activity associated with candidate FHSC Chamaeleon-MMS1 and its effect on the surrounding material to determine the evolutionary state of this young low-mass source. We observed Chamaeleon-MMS1 with the Atacama Large Millimeter/submillimeter Array at 220 GHz at high spatial (∼75 au) and spectral resolutions (0.1–0.3 km s⁻¹). A low-energy outflow is detected, consisting of two components, a broad spectral feature (Δv ∼ 8 km s⁻¹) to the northeast and narrow spectral features (Δv ∼ 1 km s⁻¹) to both the northeast and southwest. The molecular tracers CS, formaldehyde (H₂CO), and methanol (CH₃OH) were used to analyze the effect of the outflows on the surrounding gas and determine its rotational temperature. The rotational temperature of H₂CO is 40 K toward the continuum source with similarly low temperatures (10–75 K) toward clumps affected by the outflow. CH₃OH is only detected toward gas clumps located away from the continuum source, where the methanol is expected to have been released by the energy of the outflow through ice sputtering. While molecular emission and high outflow speeds rule Cha-MMS1 out as an FHSC, its outflow is less energetic than those of other Class 0 objects and its physical properties are within the range covered by other low-luminosity protostars. The inferred gas temperatures toward the continuum source are also relatively low, indicating that Cha-MMS1 is one of the youngest known sources.

中文翻译：

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Chamaeleon-MMS1 的流出活性和化学环境的高分辨率研究


小质量恒星形成的最早阶段尚不清楚，第一流体静压核心（FHSC）是前恒星和原恒星核心之间的过渡阶段。这项工作描述了与候选 FHSC Chamaeleon-MMS1 相关的局部（∼4000 au）流出活动及其对周围物质的影响，以确定这个年轻的低质量源的演化状态。我们使用阿塔卡马大型毫米/亚毫米阵列在 220 GHz、高空间（∼75 au）和光谱分辨率（0.1–0.3 km s ^-1 ）下观察了 Chamaeleon-MMS1。检测到低能量流出物，由两个成分组成，宽光谱特征（Δ v ∼ 8 km s ⁻¹ ) 向东北且窄光谱特征 (Δ v ∼ 1 km s ^-1 ) 向东北和西南方向移动。使用分子示踪剂CS、甲醛(H ₂ CO)和甲醇(CH ₃ OH)来分析流出物对周围气体的影响并确定其旋转温度。朝向连续源的 H ₂ CO 的旋转温度为 40 K，朝向受流出影响的团块的温度也类似较低 (10-75 K)。仅在远离连续源的气体团块中检测到 CH ₃ OH，其中甲醇预计已通过冰溅射流出的能量释放出来。虽然分子发射和高流出速度排除了 Cha-MMS1 作为 FHSC 的可能性，但其流出物的能量低于其他 0 类天体，并且其物理特性在其他低光度原恒星覆盖的范围内。 连续源的推断气体温度也相对较低，表明 Cha-MMS1 是已知最年轻的源之一。