Beginning with loose aggregations of dust particles coated with heterogeneous ices under vacuum at Kuiper Belt temperatures, moving to Jupiter/Saturn distances and eventually to low-perihelion orbit, we consider the likely development of the gaseous phase within a cometary nucleus over the course of its lifetime. From the perspective of physical chemistry, we consider limits on the spatial and temporal distribution and composition of this gaseous phase. The implications of the gaseous phase for heat transfer and for the possible spatial and temporal development of liquid phases are calculated. We conclude that the likely temperatures, pressures, and compositions beneath the outer crust of typical cometary nuclei are such that fluidised phases can exist at significant depths and that these reservoirs give a coherent explanation for the high-intensity outbursts observed from cometary nuclei at large distances from perihelion.

中文翻译：

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彗星内部流动相的演变

从在柯伊伯带温度下真空下覆盖着异质冰的尘埃颗粒的松散聚集开始，移动到木星/土星距离并最终移动到近日点低轨道，我们考虑了彗星核内气相可能在其过程中的发展寿命。从物理化学的角度，我们考虑了对这种气相的空间和时间分布和组成的限制。计算了气相对传热和液相可能的空间和时间发展的影响。我们得出结论，可能的温度、压力、