Science. 1993 Oct 1;262(5130):86-9. doi: 10.1126/science.262.5130.86.
Much of the interstellar gas resides in photodissociation regions whose chemistry and energy balance is controlled by the flux of far-ultraviolet radiation upon them. These photons can ionize and dissociate molecules and heat the gas through the photoelectric effect working on dust grains. These regions have been extensively modeled theoretically, but detailed observational studies are few. Mapping of the prominent Orion Bar photodissociation region at wavelengths corresponding to the carbon-hydrogen stretching mode of polycyclic aromatic hydrocarbons, the 1-0 S(1) line of molecular hydrogen, and the J = 1-0 rotational line of carbon monoxide allows the penetration of the far-ultraviolet radiation into the cloud to be traced. The results strongly support the theoretical models and show conclusively that the incident far-ultraviolet radiation field, not shocks as has sometimes been proposed, is responsible for the emission in the Orion Bar.
大部分星际气体存在于光解区域中，这些区域的化学和能量平衡受到远紫外辐射通量的控制。这些光子可以电离和分解分子，并通过光电效应加热气体，该效应作用于尘埃颗粒上。这些区域已经在理论上得到了广泛的模拟，但详细的观测研究却很少。在对应于多环芳烃碳氢伸缩模式、分子氢的 1-0 S(1)线和一氧化碳的 J = 1-0 转动线的波长上对著名的猎户座棒状光解区域进行测绘，可追踪远紫外辐射进入云的穿透情况。结果强烈支持理论模型，并明确表明，导致猎户座棒状区发射的是入射远紫外辐射场，而不是有时提出的激波。
