Chemical Theories on the Origin of Comets
Chemical Theories on the Origin of Comets
复制标题
关于彗星起源的化学理论
DOI：
10.1007/978-94-011-3378-4_16
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Tetsuo Yamamoto
中科院分区：
文献类型：
--
作者：
Tetsuo Yamamoto
首先，简要综述了目前可用于推断彗星物质形成环境物理条件的观测数据。其中包括彗星物质的化学和同位素组成，以及由H2O分子的邻位/对位丰度比得出的核自旋温度。其次，回顾了关于彗星起源的理论--基于彗星物质挥发性成分的化学成分的理论。这些理论被分为两类，根据彗星挥发物是起源于太阳星云凝聚物还是起源于星际冰的升华残留物来区分。指出了有助于检验理论的观测项目。第三，讨论了与彗星起源化学理论有关的冰的物理性质。
Firstly, observational data available at present to infer physical conditions of the formation environment of cometary matter are briefly surveyed. These include the chemical and isotopic composition of cometary matter, and the nuclear spin temperature derived from the ortho/para abundance ratio of H2O molecules. Secondly, theories on the origin of comets—theories based upon the chemical composition of the volatile component of cometary matter—are reviewed. The theories are classified into two types, distinguished by whether cometary volatiles originate as solar nebula condensates or as the sublimation residue of interstellar ices. Observational items helpful to test the theories are pointed out. Thirdly, discussion is given on the physical properties of ices relevant to the chemical theory of the origin of comets.