The History of Comets and Our Planetary System as Inferred from D/H ratio, Spin Temperature, and Native Volatile Composition

彗星是早期太阳系的遗迹，被认为是周围最原始的物体，代表了太阳系形成的物质。因此，研究彗星为理解我们的行星系统的起源和演化提供了至关重要的联系。该项目将使用高分辨率红外光谱来研究：(1)水和甲烷中的氢-氢比(D/H)，其在彗星群中的可变性，以及它与太阳系其他地方的D/H比测量结果的比较，(2)水和甲烷的自旋温度在彗星群中的变化，以及(3)彗星的有机挥发性成分的可能分类。近红外线包含每个物种的多条谱线，因此可以同时搜索多个母体分子。这项研究解决了一个紧迫的问题，即氚化度、自旋温度和彗星挥发分中的相对化学丰度如何相互关联，以及与早期太阳系的形成和演化模型之间的关系。通过了解自然挥发性丰度的多样性，该研究还从观测上解决了陆地生物圈“彗星起源”的假设。这项研究与中学和本科教育相结合，包括教育教师和培养中学生的研究项目。这将涉及主要研究领域和相关的基础领域(物理、化学和生物学)，并在两个大城市地区(华盛顿特区为Boncho Bonev博士，密苏里州圣路易斯为Copi Erika Gibb博士)。本科生将参加专业的天文观测长跑，并参加地方和国家会议。

AST-0807939BonevComets are remnants from the early solar system, and are believed to be the most primitive objects around, representative of the material from which the solar system formed. Studying comets therefore provides a vital link to understanding the origin and evolution of our planetary system. This project will use high-resolution infrared spectroscopy to investigate: (1) the deuterium-to-hydrogen (D/H) ratio in water and methane, its variability within the comet population, and how it compares with D/H ratio measurements elsewhere in the solar system, (2) how the spin temperatures of water and methane vary among the comet population, and (3) the possible classification of comets by their organic volatile composition. The near-infrared contains multiple lines of each species and thus permits the simultaneous search for a number of parent molecules. This research addresses the pressing question of how the degree of deuteration, the spin temperature, and the relative chemical abundances in cometary volatiles, relate to each other and to formation and evolution models for the early solar system. By understanding the diversity of the native volatile abundances, it also addresses observationally the hypothesis of the 'cometary origin' of the terrestrial biosphere.The research is integrated with secondary school and undergraduate education, including educating teachers and fostering research projects for secondary school students. This will involve both the primary research area and related fundamental fields (physics, chemistry, and biology), and in both metropolitan areas (Washington, DC for PI Dr Boncho Bonev, and Saint Louis, MO for CoPI Dr Erika Gibb). Undergraduate student participants will take part in professional astronomical observing runs and in local and national conferences.