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

这个项目将利用里希特博士开发的独特观测技术来推进我们对行星起源的理解。在双子座北8号上使用德克萨斯梯队-交叉梯队光谱仪。他将利用1米高的望远镜，观察目前认为在年轻恒星周围形成行星的物质。结果将与星周盘参数有关，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处的气体化学成分。这些观察将采用双管齐下的方法。首先，里希特博士将在25个已知的星周圆盘中，从氢分子的纯旋转光谱线中寻找圆盘发射的明确光谱特征。摄谱仪的分辨率将允许研究盘线轮廓，从中可以推断出气体温度和热气体质量，这是最好的探测。在这些圆盘之后，将对其他重要分子进行观测，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，将提供对这些年轻恒星系统中行星形成区域的物理过程的深入了解。该项目还将确保天文学界继续使用这种独特的仪器，它填补了波长覆盖范围长达25微米的重要空白，提供了卓越的灵敏度，并且具有远高于中红外空间的光谱分辨率。一名研究生还将接受仪器和大型光学望远镜观测方面的培训。作为博士论文的一部分，研究生也将维护、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.