Extended Red Emission (ERE) in Planetary Nebulae

扩展红发射（ERE）是一种尘埃发光过程，最近被认为是由氢化非晶碳的光致发光引起的。如果它的存在可以在银河系尺度上被证明，特别是在尘埃形成的环境中，那么就必须将其视为一种重要尘埃化合物（即无定形碳）存在及其物理结构的直接观测证据。行星状星云被认为是新星际尘埃的主要来源之一，有一些证据表明，ERE很可能存在于许多这样的天体中。行星状星云也显示出大量尘埃颗粒加工的证据。维特博士将对24个行星状星云在3200至10000埃波长范围内的光学连续体进行观测研究。他的目标是研究ERE的强度和光谱作为这些星云中碳氧比的函数，以及作为存在的尘埃颗粒大小分布的函数。

Extended red emission (ERE) is a dust luminescence process which has recently been attributed to photoluminescence by hydrogenated amorphous carbon. If its presence can be demonstrated on a galactic scale and, in particular, in dust forming environments, ERE must be considered direct observational evidence for the presence and physical structure of an important dust compound, that is, amorphous carbon. Planetary nebulae are recognized as one of the major sources of new interstellar dust, and there is some evidence that ERE is very likely to be present in many of these objects. Planetary nebulae also exhibit evidence for substantial dust grain processing. Dr. Witt will carry out observational studies of the optical continuum in the wavelength range of 3200 to 10,000 Angstroms of 24 planetary nebulae. His aim is to investigate the strength and the spectrum of ERE as a function of the carbon to oxygen ratio in these nebulae and as a function of the size distribution of the dust grains present.