射电天文研究组知识库

W51M （W51 Main）是一个和HⅡ区成协的大质量恒星形成区,在其中可以探测到众多的分子谱线和H、He射电复合线.中国科学院上海天文台基于天马65 m望远镜对W51M的观测数据,证认了主量子数在74–117之间的H、He复合发射线,其中主量子数在74–78之间的H和He的α复合线均被探测到.结合H和He复合线的多普勒致宽,算出该HⅡ区的电子温度约为7400 K, He+/H+的离子丰度比约为0.09,这与已有的研究基本吻合.考虑高信噪比的复合线,即H（n）α（74n78）,计算得出W51M的平均湍动速度是13.767 km·s-1.通过确定W51M或其他HⅡ区中的复合线,获取电子温度、湍动速度以及其他物理参量,在电子数密度、元素丰度、恒星形成率等方面进行了探讨,对分子谱线以及其他波段的复合线研究具有借鉴意义. 

W51M (W51 Main) is a massive star-forming region associated with the HII region, in which numerous molecular lines, H and He recombination lines can be detected. Study of these lines is helpful to understand the properties and physical environment of W51M. Based on the observation data of the Tianma 65-meter telescope, owned by Shanghai Astronomical Observatory, Chinese Academy of Sciences, the H and He recombination lines of the main quantum number between 74 and 117 were detected. Combined with their Doppler broadening, the electron temperature of the nebula was calculated. It was found that the electron temperature of the HII region was about 7400 K, and the He+/H+ ionic abundance ratio was about 0.09, which was basically consistent with previous results. Considering the high signal-to-noise ratio of those recombination lines, i.e. H(n)α (74 6 n 6 78), the calculated average turbulent velocity of W51M is 13.767 km·s−1. This work discusses the identification of recombination lines in W51M or other HII regions, and the acquisition of electron temperature, turbulent velocity, and other physical parameters, such as electron number density, the element abundance, and star formation rate. So it is of positive significance for future study.