星周致密HII区的电离平衡和非热动平衡效应

本文在球对称几何、纯氢、等温、稳态质量损失及Sobolev近似下研究内嵌星周致密HII区中的电离平衡及非热动平衡(NLTE)效应。研究表明,致密HII区严重偏离热动平衡,碰撞电离及激发态光致电离对HII区大小、NLTE偏离因子分布及谱线观测流量比产生重大影响,用它们可解释YSOs源的红外谱线流量超和流量短缺现象,指出不能用光学薄谱线复合理论推断内嵌中央星的光谱型、质量损失率及前景消光。     

超致密电离氢区周围的CO高速气体

给出了与星际水脉泽源和超致密电离氢区成协的77个恒星形成区的高速¹²CO（J＝1-0）分子辐射的搜寻结果. 目的是调查高速分子外流、星际H2O脉泽源和它们所联系的红外源之间的关系. 样本满足WC标准，即：lg(F_25μm/F_12μm)＞0.57和lg(F_60μm/F_12μm)＞1.3.绝大多数源都存在着气体的高速运动，在1σT*_a水平处，几乎70％的源的谱线全宽(FW）超过15 km·s^-1，15％的源则超过了30 km·s^-1.这个结果极大地超过了小质量恒星形成区所得到的值.在CO分子的FW，半峰全宽（FWHM）和源的红外光度之间存在清楚的相关性，两种线宽的值正比于红外光度的值.这些关系表明了亮源能够注入更多的能量进入它周围物质中从而产生更强有力的外流使得CO分子的线宽增大.从CO分子和水脉泽的峰值速度的对应关系中发现一些水脉泽源相对于其附近的气体呈现出大的蓝移，这也许是由非饱和脉泽放大了背景源引起的.     

High-velocity gas associated ultracompact HII regions

We present the results of a survey for high-velocity¹²CO (1-0) emission associated H₂O masers and ultracompact (UC) HII regions. The aim is to investigate the relationship between H₂O masers, CO high-velocity gas (HVG) and their associated infrared sources. Our sample satisfies Wood & Churchwell criterion. Almost 70 % of the sources have full widths (FWs) greater than 15 km · s^-1 atT* _a = 100 mK and 15 % have FWs greater than 30 km · s^-1 In most of our objects there is excess high velocity emission in the beam. There is a clear correlation between CO line FWs and far-infrared luminosities: the FW increases with the FIR luminosity. The relation suggests that more luminous sources are likely to be more energetic and able to inject more energy into their surroundings. As a result, larger FW of the CO line could be produced. In most of our sources, the velocities of peak of the H₂O emission are in agreement with those of the CO cloud, but a number of them have a large blueshift with respect to the CO peak. These masers might stem from the amplifications of a background source, which may amplify some unobservable weak masers to an observable level.