High-resolution, mid-infrared spectroscopy of young stellar environments

这个项目将利用部分由里希特博士开发的独特的观测技术来促进我们对行星起源的理解。使用双子座北8米望远镜上的德州梯形交叉回声光谱仪，他将观察目前被认为是围绕年轻恒星形成行星的物质。结果将影响到星盘参数，如气体温度、气体扩散时间、径向混合程度、尘埃颗粒的沉降和/或生长，以及行星形成半径的气体化学成分。这些观测将采取双管齐下的方法。首先，里希特博士将在25个已知的环绕恒星的圆盘中，从分子氢的纯旋转光谱线中寻找圆盘发射的明确光谱特征。光谱仪的分辨率将允许研究盘线轮廓，从而有可能在最佳探测中推断气体温度和热气体质量。在这些圆盘之后，还将观察到其他重要的分子，包括水、乙炔和氰化氢。这些分子的丰度，以及原行星盘的化学模型，将提供对参与这些年轻恒星系统行星形成区域的物理过程的洞察。该项目还将确保天文学团体继续使用这台独特的仪器，它填补了长达25微米的波长覆盖范围的一个重要空白，提供了非凡的灵敏度，并具有比太空中红外光谱分辨率高得多的光谱分辨率。一名研究生还将接受大型光学望远镜仪器和观测方面的培训。作为博士论文的一部分，将在这里支持的研究生还将维护、操作和改进光谱仪。

This project will utilize the unique observational technology developed in part by Dr. Richter to advance our understanding of the origin of planets. Using the Texas Echelon-cross-Echelle Spectrograph on the Gemini North 8.-meter telescope, he will observe the material from which planets are currently believed to be forming around young stars. The results will bear on circumstellar disk parameters such as the gas temperatures, gas dispersal time, degree of radial mixing, settling and/or growth of dust grains, and gas chemical composition at planet forming radii.These observations will follow a two-pronged approach. First Dr. Richter will search for unambiguous spectral signatures of disk emission in the pure rotational spectral lines of molecular hydrogen among 25 known circumstellar disks. The resolution of the spectrograph will allow the study of the disk line profiles from which it will be possible to infer gas temperatures and warm gas masses among the best detections. These disks will be followed up with observations of other important molecules, including water, acetylene, and hydrogen cyanide. The abundances of these molecules, along with chemical models of protoplanetary disks, will provide insight into the physical processes taking part in the planet forming regions of these young stellar systems.This project will also assure continued access by the astronomical community to this unique instrument, which fills an important gap in wavelength coverage long ward of 25 microns, offers exceptional sensitivity, and has far greater spectral resolution than is possible from space in the mid-infrared. A graduate student will also be trained in instrumentation and observing on large optical telescopes. The graduate student to be supported here will also maintain, operate and improve the spectrograph as part of a Ph.D. dissertation.