摘要
本文根据NGC7538的红外和分子谱线观测结果,对红外源的热结构及成协气体的热平衡进行了计算和分析。得出尘埃温度随半径的分布T_d a r^(-0.36)其峰值温度略高于已有观测结果,并发现除中心源附近区域外,大部分区域内不再满足尘埃通过碰撞向气体输入能量的基本条件。本文计算了NGC7538气体的冷却串及多种机制的加热作用,结果表明宇宙线、坍缩及双极扩散等机制的加热率相对较小,而尘埃通过光电作用对气体的加热可能是气体的重要热源。
The thermal structure of the infrared sources in NGC7538 and the thermal balance of the associated gas are analysed and the cooling and heating rats are calculated baaed on tbe observations of infrared and miolimeter wave molecular lines. The results show that the relation between the dust temperature distribution and the distance to the center can be written as Tdar-0.38. ComparingTd to Tk observed from COJ = 1-0, we find that for most part of the cloud the collisions between dust grains and gas molecules can hardly to maintain the gas at the observed temperature.Various heating mechanisms have been calculated and/or discussed. It is found that the photoelectric mechinism may be an important heating source for the gas in NOD7538.
出处
《北京大学学报（自然科学版）》
CAS
CSCD
北大核心
1991年第3期323-329,共7页
Acta Scientiarum Naturalium Universitatis Pekinensis
基金
国家自然科学基金
