标题： 用ALMA高分辨率观测揭示OMC-3/MMS 3中的中心凝聚结构 显示英文标题

标题： Revealing a Centrally Condensed Structure in OMC-3/MMS 3 with ALMA High Resolution Observations

摘要： 使用阿塔卡马大型毫米/亚毫米波阵列（ALMA），我们在1.3毫米连续谱、CO（$J$=2-1）、SiO（$J$=5-4）、C$^{18}$O（$J$=2-1）、N$_2$D$^+$（$J$=3-2）、和DCN（$J$=3-2）发射线中研究了一个特殊的毫米源MMS 3，该源位于猎户座分子云3（OMC-3）区域。 随着ALMA的高角分辨率（$\sim$0''.2），我们检测到一个非常紧凑且高度中心凝聚的连续谱辐射，尺寸为0''.45$\times$0''.32（P.A.=0.22$^\circ$）。 峰值位置与之前报道的$Spitzer$/IRAC和X射线源的位置在它们的定位误差范围内一致。 我们还检测到一个直径为$\sim$6800 au 的包层 (P.A.=75$^\circ$)，在 C$^{18}$O ($J$=2-1) 辐射中。此外，在 CO ($J$=2-1) 辐射中首次检测到一个双极喷流。该喷流大致垂直于在 C$^{18}$O ($J$=2-1) 辐射中检测到的包层的长轴。 在22-30 km s$^{-1}$的（红移）速度范围内检测到致密的高速CO气体，可能追踪到喷流，位于1.3 mm连续谱峰值附近。 在CO喷流叶瓣上略微检测到一个紧凑而微弱的红移SiO发射。 MMS 3中的喷流物理量相对于OMC-3区域其他源来说相对较小。 与近红外和X射线源相关的中心凝聚天体、扁平包层以及微弱的喷流表明，MMS 3包含一个年龄为$\sim$10$^3$年的低质量原恒星。 显示英文摘要

摘要： Using the Atacama Large Millimeter/submillimeter Array (ALMA), we investigated a peculiar millimeter source MMS 3 located in the Orion Molecular Cloud 3 (OMC-3) region in the 1.3 mm continuum, CO ($J$=2-1), SiO ($J$=5-4), C$^{18}$O ($J$=2-1), N$_2$D$^+$ ($J$=3-2), and DCN ($J$=3-2) emissions. With the ALMA high angular resolution ($\sim$0''.2), we detected a very compact and highly centrally condensed continuum emission with a size of 0''.45 $\times$ 0''.32 (P.A.=0.22$^\circ$). The peak position coincides with the locations of previously reported $Spitzer$/IRAC and X-ray sources within their positional uncertainties. We also detected an envelope with a diameter of $\sim$6800 au (P.A.=75$^\circ$) in the C$^{18}$O ($J$=2-1) emission. Moreover, a bipolar outflow was detected in the CO ($J$=2-1) emission for the first time. The outflow elongates roughly perpendicular to the long axis of the envelope detected in the C$^{18}$O ($J$=2-1) emission. Compact high-velocity CO gas in the (red-shifted) velocity range of 22-30 km s$^{-1}$, presumably tracing a jet, was detected near the 1.3 mm continuum peak. A compact and faint red-shifted SiO emission was marginally detected on the CO outflow lobe. The physical quantities of the outflow in MMS 3 are relatively smaller than those in other sources in the OMC-3 region. The centrally condensed object associated with the near-infrared and X-ray sources, the flattened envelope, and the faint outflow indicate that MMS 3 harbors a low mass protostar with an age of $\sim$10$^3$ yr.