摘要
本文在分析研究NGC7538-IRS1致密HⅡ区H_2CO和OH脉泽辐射VLBI观测结果的基础上,指出该HⅡ区合理的模型是:HⅡ区表面为厚的尘埃层包围,尘埃层两极已被突破,并形成双极流;HⅡ区外面有一个环形转动气体-尘埃云,存在由环向HⅡ区表面的物质下落;包括环和HⅡ区在内的整个系统视向速度为-61km/s,该系统居于视向速度为-57km/s的更大分子云中。H_2CO和OH脉泽发生在HⅡ区两极附近离HⅡ区表面小于0.2R_(HⅡ)的区域内。利用上述模型,还讨论了H_2O脉泽及其他分子吸收线和发射线的发生区域。
Based on the analysis of VLBI observation: of H2CO and OH maser emission in the direction of the ultracompact HII region of NGC7538-IRS1, this paper shows a reasonable mode! of this HII region: The HII region is bound by a thick dust shell which breaks open at its two poles and bipolar outflows occur at these two poles; Around the HII region is a gas-dust ring from which the material is falling to the surface of the HII region; The whole system, including the HII region and the gas-dust ring, moves at a sight line velocity of -61.0 km/s in a large cloud that has a sight line velocity of - 57 km/s. The places where the H2CO and OH maser emission occurs are near the poles of the HII region, and close to the surface of HII region within 0.2 RHII. According to this model the positions of H2O maser,and other molecular absorption and emission line sources are discussed.
关键词
恒星形成
HⅡ区
分子云
Stars: formation of-HII region-Molecular cloud
