标题： 关于分子云核心的气体温度 显示英文标题

标题： On The Gas Temperature of Molecular Cloud Cores

摘要： 我们研究影响星际云致密核心温度分布的不确定性。 在受到外部紫外线辐射屏蔽的区域，问题简化为宇宙射线加热、线冷却以及气体和尘埃之间的耦合之间的平衡。 我们表明，气相丰度、颗粒大小分布和速度场的变化各自可以使预测的核心温度变化一到两度。 我们强调非局部辐射转移效应的作用，这些效应通常在建模核心化学时未被考虑。 这些包括不同温度区域之间的辐射耦合以及云表面附近的增强线冷却。 温度分布的不确定性不一定会导致从观测中得出的柱密度出现显著误差。 然而，耗竭过程对温度非常敏感，两度的差异可能意味着某种分子不再追踪核心中心的物理条件。 显示英文摘要

摘要： We investigate the uncertainties affecting the temperature profiles of dense cores of interstellar clouds. In regions shielded from external ultraviolet radiation, the problem is reduced to the balance between cosmic ray heating, line cooling, and the coupling between gas and dust. We show that variations in the gas phase abundances, the grain size distribution, and the velocity field can each change the predicted core temperatures by one or two degrees. We emphasize the role of non-local radiative transfer effects that often are not taken into account, for example, when modelling the core chemistry. These include the radiative coupling between regions of different temperature and the enhanced line cooling near the cloud surface. The uncertainty of the temperature profiles does not necessarily translate to a significant error in the column density derived from observations. However, depletion processes are very temperature sensitive and a two degree difference can mean that a given molecule no longer traces the physical conditions in the core centre.