U.S.-Australia Cooperative Research on Carbon Isotopes in Comets

美国PIS之一彼得·A·韦辛格、苏珊·怀科夫和他们的研究生马文·克莱恩将拜访澳大利亚同行澳大利亚国立大学的布鲁斯·A·彼得森博士，每三年一次。这项研究的目标是确定明亮彗星样本中的碳同位素丰度比，并通过观测分子和分子离子(CN，CH，和CH+)在明亮的0型和B型恒星的视线内。此外，还建议建立一个完整的CN荧光模型，以提高测定彗星碳、氮同位素比值的准确度。研究人员将使用位于澳大利亚堪培拉附近的斯特罗莫洛山天文台1.9米的望远镜，以及它的梯形光谱仪和光计数阵列。在北半球，调查人员将使用基特峰国家天文台的对数馈电望远镜和梯形光谱仪。这项研究基本上是1986年与哈雷彗星在美澳合作科学计划支持下开始的成功合作努力的延续，之所以重要，是因为它可能揭示了早期宇宙的形成。对美国国内研究的额外财政支持来自NASA和NSF的拨款。

One of the U.S. PIs, Peter A. Wehinger, Susan Wyckoff, and their graduate student, Marvin Kleine, will visit their Australian counterpart, Dr. Bruce A. Peterson of the Australian National University, once in each of three years. The goals of this research are to determine the carbon isotope abundance ratio in a sample of bright comets, and to determine the 12C/13C abundance ratio in the local interstellar medium by observing absorption lines of molecules and molecular ions (CN, CH, and CH+) in the lines-of-sight of bright 0- and B-type stars. Also proposed is the development of a full fluorescence model for CN to improve the accuracy with which we can determine the carbon and nitrogen isotope ratios in comets. The researchers will use the Mount Stromolo Observatory's 1.9 meter telescope located near Canberra, Australia, with its coude-echelle spectrograph and photo-counting array. In the Northern Hemisphere, the investigators will use the Kitt Peak National Observatory coude-feed telescope and echelle spectrograph. The research, which is essentially a continuation of a successful collaborative effort begun with Comet Halley in 1986 with U.S.-Australia Cooperative Science Program support, is important because of what it may reveal about the formation of the early universe. Additional financial support for the domestic U.S. research comes from NASA and NSF grants.