VLA Observations of H2O Masers in the Class 0 Protostar S106 FIR: Evidence for a 10 AU Scale Accelerating Jetlike Flow
VLA Observations of H2O Masers in the Class 0 Protostar S106 FIR: Evidence for a 10 AU Scale Accelerating Jetlike Flow
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VLA 对 0 级原星 S106 FIR 中 H2O 脉泽的观测：10 AU 规模加速喷射流的证据
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发表时间：
1999
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通讯作者：
R. Furuya
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作者：
R. Furuya
我们对0级源S106 FIR（d = 600 pc; S106 IRS 4以西15 "）的22 GHz水脉泽进行了0.“06分辨率的VLA观测，观测时间间隔约为3个月。在S106远红外区亚毫米核的中心发现了两个紧凑的脉泽光斑群。沿沿着P. A，簇的分离为~80 mas（48 Au）。= 70°，每个簇的大小约为20 mas × 10 mas。西部集群，其中有三个微波激射组件，是8.0公里秒-1蓝移，和东部集群，其中有一个单一的组件，是7.0公里秒-1红移相对于周围的云速度。每个组成部分是由几个空间定位的脉泽斑点，并在一条线上连接集群对齐。我们发现的组件的相对自行与3000万秒yr-1（18 Au yr-1）沿着。此外，一系列的单碟观测表明，脉泽组件漂移的径向加速度约为1公里s-1年-1。这些事实表明，脉泽可以激发一个10 Au尺度的喷流加速从一个假设的原恒星位于两个集群之间的喷射。由脉泽各分量的相对自行和径向速度推算出的脉泽出流大小经10°倾角校正后为50 Au × 5 Au。三维外流速度范围从40至70公里s-1假设对称自行的蓝色和红色的组件。由于没有明显的CO分子外流已被检测到，到目前为止，我们认为，S106 FIR是一个非常年轻的原恒星观察后，外流活动的发病。
We conducted VLA observations at 0.″06 resolution of the 22 GHz water masers toward the Class 0 source S106 FIR (d = 600 pc; 15′′ west of S106 IRS 4) on two epochs separated by ~3 months. Two compact clusters of the maser spots were found in the center of the submillimeter core of S106 FIR. The separation of the clusters was ~80 mas (48 AU) along P.A. = 70°, and the size of each cluster was ~20 mas × 10 mas. The western cluster, which had three maser components, was 8.0 km s-1 blueshifted, and the eastern cluster, which had a single component, was 7.0 km s-1 redshifted with respect to the ambient cloud velocity. Each component was composed of a few spatially localized maser spots and was aligned on a line connecting the clusters. We found relative proper motions of the components with ≈30 mas yr-1 (18 AU yr-1) along the line. In addition, a series of single-dish observations shows that the maser components drifted with radial accelerations of ~1 km s-1 yr-1. These facts indicate that the masers could be excited by a 10 AU scale jetlike accelerating flow ejected from an assumed protostar located between the two clusters. The outflow size traced by the masers was 50 AU × 5 AU after correction for an inclination angle of 10°, which was derived from the relative proper motions and radial velocities of the maser components. The three-dimensional outflow velocity ranged from 40 to 70 km s-1 assuming symmetric proper motions for the blue and red components. Since no distinct CO molecular outflows have been detected so far, we suggest that S106 FIR is an extremely young protostar observed just after the onset of outflowing activity.