Collaborative Research: Carriers, Charge State, and Diagnostic Use of the Long-Mysterious Diffuse Interstellar Bands

合作研究：长期神秘的弥漫星际带的载流子、电荷态和诊断用途

• 批准号: 1238926
• 负责人: Daniel Welty
• 金额: $ 9.77万
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2014-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1238926&HistoricalAwards=false
• 关键词: Collaborative; Research; Carriers; Charge; State

This work investigates which atoms, ions, small and large molecules cause certain interstellar absorption features known as "Diffuse Interstellar Bands" (DIBs). About 600 absorption lines associated with these families of interstellar bands are known since the 1920s but their association which specific molecules is still unknown. Here researchers with different expertise in atomic and molecular spectroscopy, interstellar gas and dust, and laboratory chemistry, come together to tackle this long-standing open question. The approach is to compile and organize existing observations in databases and to add new measurements of DIBs seen toward about 220 stars to assess and to search for empirical relations between the different DIB absorption features as well as other interstellar parameters such as density and ionization state. The existing list of DIBs of all spectral widths to uniform limit is expanded with new observations to include broad and narrow lines that only appear under certain physical conditions. For this purpose, a new atlas of stars illuminating such interstellar regions will be assembled. Another goal is to observe certain diffuse interstellar clouds to obtain the types and absorption strengths of DIBs as a function of increasing density and ionization state, which relates to the spatial distribution of particular compounds and on-going reactions within the cloud. The team members have guaranteed access to observing facilities (e.g., Apache Point Observatory) to do this part of work.As long as the types of compounds (molecules with more than 15 atoms are suspected) responsible for the DIB absorptions remain elusive, it is not possible to fully account for the chemical inventory and processes of the interstellar medium. The identification of the carriers of the DIBs will be a major step forward in understanding the chemical inventory in molecular clouds from which stars and planets form.The interdisciplinary nature of this collaborative project is very strong. It provides undergraduate- and graduate students with opportunities to work on problems related to more than one discipline.

这项工作调查了哪些原子，离子，小分子和大分子导致某些星际吸收特征，称为“弥漫星际带”（DIB）。自20世纪20年代以来，已知约有600条与这些星际带家族相关的吸收线，但它们与哪些特定分子的关联仍然未知。在这里，在原子和分子光谱学、星际气体和尘埃以及实验室化学方面具有不同专业知识的研究人员聚集在一起，共同解决这个长期存在的悬而未决的问题。该方法是编译和组织数据库中现有的观测数据，并增加对大约220颗恒星的DIB的新测量，以评估和搜索不同DIB吸收特征以及其他星际参数（如密度和电离状态）之间的经验关系。现有的所有光谱宽度统一限制的DIB列表扩展了新的观测，包括仅在某些物理条件下出现的宽线和窄线。为此，将编制一个新的恒星图集，以照亮这些星际区域。另一个目标是观察某些弥漫的星际云，以获得作为密度和电离状态增加的函数的DIB的类型和吸收强度，这与特定化合物的空间分布和云中正在进行的反应有关。小组成员保证可以使用观测设施（例如，只要引起DIB散射的化合物（分子中原子数超过15的分子被怀疑）的类型仍然不清楚，就不可能完全解释星际介质的化学物质和过程。对DIB载体的识别将是理解恒星和行星形成的分子云中化学物质清单的重要一步。这一合作项目的跨学科性质非常强。它为本科生和研究生提供研究与多个学科相关的问题的机会。