Astrochemistry: Hydrodynamics, Cosmic ray induced ice chemistry, and Complex Molecules

天体化学是研究宇宙中分子类型及其化学的学科。遥远地区的分子本身很有趣，可以作为不同地区物理条件的探测器，特别是被称为致密星际云的地区。恒星和行星是在这些云层中形成的，云层中充满了分子，其中一些以地球标准来看是相当奇怪的。研究人员将研究星际云坍塌和升温时发生的化学物质。他们将确定哪些化学反应是最重要的，并模拟这些区域化学成分的变化。云坍塌的最终产物是像太阳这样的低质量恒星，以及远比太阳明亮的大质量恒星。有机(含碳)分子的合成特别令人感兴趣，因为这些分子可以成为新生行星的一部分，并经常与生命联系在一起。天体化学的一个关键方面是使用化学模拟来重现对气体和尘埃颗粒中分子丰度的观测研究，从而了解星际和星际周围介质中的源寿命和物理条件。化学模拟包括求解所谓的耦合动力学微分方程组，该方程产生许多分子的柱、丰度甚至光谱作为密度、温度和非均质程度的函数。我们的主要兴趣将是研究恒星的形成。鉴于目前和未来的干涉仪，重点将放在研究恒星形成过程中的源的动力学和异质性，包括低质量和高质量类别。特别是，三维流体力学将与化学模拟相结合，最初的目标是了解在低质量源中形成原行星盘期间发生的化学作用，以及在高质量源中形成红外暗云、高质量原恒星天体(HMPO)和热核期间发生的化学作用。对化学的详细了解应该会产生许多关于恒星形成的细节的信息。

Astrochemistry is the study of the types of molecules and their chemistry throughout the universe. Molecules in far-away regions are interesting in themselves and as probes of the physical conditions in various regions, especially regions known as dense interstellar clouds. Stars and planets form in these clouds, which are full of molecules, some quite exotic by terrestrial standards. The investigators will study the chemistry that occurs as interstellar clouds collapse and warm up. They will determine which chemical reactions are most important and simulate the changes in the chemical composition of these regions. The final products of the cloud collapse are low-mass stars, like the sun, as well as high-mass stars, which are far brighter than the sun. The synthesis of organic (carbon-containing) molecules is of special interest, since these molecules can become part of nascent planets and are often associated with life. One critical aspect of astrochemistry is the use of chemical simulations to reproduce observational studies of molecular abundances in the gas and on dust particles, and so learn about source lifetimes and physical conditions in the interstellar and circumstellar media. The chemical simulations involve the solution of so-called coupled kinetic differential equations, which yields columns, abundances, or even spectra of many molecules as functions of density, temperature, and degree of heterogeneity. Our primary interest will be to study star formation. Given current and future interferometers, emphasis will be placed on studying the dynamics and heterogeneity of sources undergoing star formation, both the low-mass and high-mass categories. In particular, three-dimensional hydrodynamics will be combined with chemical simulations with the initial goal of understanding the chemistry that occurs during the formation of protoplanetary disks in low-mass sources, and infrared dark clouds, high-mass protostellar objects (HMPOs), and hot cores in high-mass sources. A detailed understanding of the chemistry should yield much information about the details of star formation.