Photo-excitation and Destruction of Specific Polycyclic Aromatic Hydrocarbon Molecules in Interstellar Space and Circumstellar Dust Disks

密苏里-哥伦比亚大学的Aigen Li博士将研究特定的多环芳烃(PAH)分子在(1)星际尘埃盘和(2)银河系星际介质、低金属丰度星系和活动星系核(AGN)中的光激发和破坏。与之前大多数专注于“天文-多环芳烃”(不代表任何特定物质，但近似于多环芳烃混合物在天体物理区域的实际吸收性质)的建模工作不同，该项目将采用统计-机械方法，研究21个特定的多环芳烃分子及其离子，范围从萘C10H8到环冠C54H18。这项工作将是对S最近的两个斯皮策理论计划的补充，这两个计划旨在研究尘埃盘、低金属丰度星系和活动星系核中天文多环芳烃的光物理。这项研究的主要成果-(1)计算出尘埃盘以及银河系和外部星系星际介质中21种特定多环芳烃分子及其离子的发射光谱，以及(2)这21种特定多环芳烃在不同天体物理环境下被紫外线和X射线光子破坏的速率-将向社会提供，并将用于广泛的科学研究。这项研究还将对培养研究生和发展密苏里大学哥伦比亚分校的天文学项目产生积极影响。

Dr. Aigen Li of the University of Missouri-Columbia will investigate the photo-excitation and destruction of specific polycyclic aromatic hydrocarbon (PAH) molecules in (1) circumstellar dust disks, and (2) the interstellar medium of the Milky Way Galaxy, low metallicity galaxies, and active galactic nuclei (AGNs). In contrast to most previous modeling efforts which focus on "astro-PAHs" (which do not represent any specific material, but approximate the actual absorption properties of the PAH mixture in astrophysical regions), this project, taking a statistical-mechanical approach, will study 21 specific PAH molecules and their ions, ranging from naphthalene C10H8 to circumcoronene C54H18. This work will complement the PI''s two recent Spitzer Theory Programs which aim at the photophysics of astro-PAHs in dust disks, low metallicity galaxies, and AGNs.The major outcomes of this research - (1) the emission spectra calculated for 21 specific PAH molecules and their ions in dust disks and in the interstellar medium of the Milky Way and external galaxies, and (2) the destruction rates of these 21 specific PAHs by ultraviolet and X-ray photons in various astrophysical environments - will be made available to the community, and will be useful for a broad range of scientific studies. This research will also have a positive impact on training graduate students and on developing an astronomy program at the University of Missouri-Columbia.