Chemical Composition of Comets

1985-1988年，哈雷彗星的出现开启了探测早期太阳星云中化学丰度的新时代，GIOTTO宇宙飞船收集了原位气体样本。此外，在大型地面望远镜上使用最先进的探测器产生了高质量的分光光度数据，非常适合于确定彗星核挥发性成分的化学丰度。这笔拨款支持对彗星核中挥发物丰度的研究。最终目标是将这些丰度与原始太阳星云中形成彗星的环境联系起来。该方法是结合观测学家和理论学家的努力，利用高质量的地面数据来约束彗星昏迷的化学模型。该模型包含了重要的化学和光解昏迷过程，将用于推导原子核中亲本物质的丰度。从这项研究中，研究人员希望得出45亿年前发生在太阳星云最冷区域的化学过程的重要限制。

The appearance of comet Halley in 1985-1988 opened a new era in probing chemical abundances in the early solar nebula with the collection of in situ gas samples by the GIOTTO spacecraft. Moreover, use of state-of-the-art detectors on large ground-based telescopes produced high quality spectrophotometric data ideally suited for determining chemical abundances of the volatile component of the comet nucleus. This grant supports the investigation of the abundances of volatiles in cometary nuclei. The ultimate goal is to relate these abundances to the environment for forming comets in the primitive solar nebula. The approach is to combine efforts of an observationalist and a theorist to constrain a chemical model of a comet coma using high quality ground-based data. The model which incorporates significant chemical and photolytic coma processes will be used to derive the abundances of the parent species in the nucleus. From this research the investigators hope to derive significant constraints on chemical processes which occurred in the coldest regions of the solar nebula 4.5 billion years ago.