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博士将研究特定多环芳烃（PAH）分子在（1）星周尘埃盘，（2）银河系星际介质，低金属量星系和活动星系核（AGN）中的光激发和破坏。与大多数以前专注于“天体多环芳烃”（不代表任何特定物质，但近似于天体物理区域中多环芳烃混合物的实际吸收特性）的建模工作相反，该项目采用物理力学方法，将研究21种特定的多环芳烃分子及其离子，范围从萘C10 H8到环冠烯C54 H18。 本研究的主要成果是：（1）计算了21种特定PAH分子及其离子在尘埃盘、银河系和外星系星际介质中的发射光谱;（2）计算了21种PAH分子及其离子在尘埃盘、银河系和外星系星际介质中的发射光谱;及（2）这21种特定多环芳烃在不同天体物理环境中被紫外线和X射线光子破坏的速率。这项研究也将对培养研究生和在密苏里-哥伦比亚大学发展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.