We present deep high-angular resolution observations of the high-mass protostar NGC?7538?S, which is in the center of a cold dense cloud core with a radius of 0.5 pc and a mass of ~2000 M ☉. These observations show that NGC?7538?S is embedded in a compact elliptical core with a mass of 85-115 M ☉. The star is surrounded by a rotating accretion disk, which powers a very young, hot molecular outflow approximately perpendicular to the rotating accretion disk. The accretion rate is very high, ~(1.4-2.8) × 10–3 M ☉?yr–1. Evidence for rotation of the disk surrounding the star is seen in all largely optically thin molecular tracers, H13CN J?= 1 → 0, HN13C J?= 1 → 0, H13CO+ J?= 1 → 0, and DCN J?= 3 → 2. Many molecules appear to be affected by the hot molecular outflow, including DCN and H13CO+. The emission from CH3CN, which has often been used to trace disk rotation in young high-mass stars, is dominated by the outflow, especially at higher K levels. Our new high angular resolution observations show that the rotationally supported part of the disk is smaller than we previously estimated. The enclosed mass of the inner, rotationally supported part of the disk (D ~ 5'', i.e., 14,000?AU) is ~14-24 M ☉.
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机译:我们提出了高质量的原恒星NGC?7538?S的深高角分辨率观测结果,它位于半径为0.5 pc,质量约为2000 M a的冷致密云芯的中心。这些观察结果表明,NGC?7538?S嵌入质量为85-115 M compact的紧凑椭圆形核中。恒星被旋转的吸积盘围绕,该吸积盘为非常年轻的热分子流出提供动力,该流出大致垂直于旋转的吸积盘。吸积率非常高,约为(1.4-2.8)×10–3 M yr-1。在所有高度光学上薄的分子示踪剂中都可以看到围绕恒星盘旋转的证据,H13CNJα= 1→0,HN13CJα= 1 = 0,H13CO +Jα= 1→0,而DCNJα= 3→ 2.许多分子似乎受热分子流出的影响,包括DCN和H13CO +。 CH3CN的排放通常被用来追踪年轻的高质量恒星中的盘旋转,其排放主要是流出,尤其是在较高的K水平下。我们新的高角度分辨率观测结果表明,磁盘的旋转支撑部分比我们之前估计的要小。盘的内部,旋转支撑部分的封闭质量(D〜5英寸,即14,000?AU)为〜14-24 M☉。
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