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

AST-0807939 BonevComets是早期太阳系的残留物，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行星系统的起源和演化提供了重要的联系。 该项目将使用高分辨率红外光谱来研究：（1）水和甲烷中的氘氢比（D/H），它在彗星群中的变化，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如何在彗星群中变化，（3）根据彗星的有机挥发成分对彗星进行分类的可能性。 近红外包含每个物种的多条谱线，因此允许同时搜索许多母体分子。 这项研究解决了一个紧迫的问题，即氘化程度、自旋温度和彗星挥发物的相对化学丰度如何相互关联，以及与早期太阳系形成和演化模型的关系。 通过了解天然挥发物丰度的多样性，它还从观测上解决了地球生物圈“彗星起源”的假设。研究与中学和大学教育相结合，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（物理学，化学和生物学），并在两个大都市地区（华盛顿，DC为PI博士Boncho Bonev，和圣刘易斯，MO为CoPI博士Erika Gibb）。 本科生参与者将参加专业天文观测运行和地方和国家会议。

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.