Gas in the Planet-Forming Region of Circumstellar Disks: High Dispersion Infrared Spectroscopy and Spectro-Astrometry

杰弗里·布莱克博士(加州理工学院)将领导一个与莱顿大学研究人员合作的研究项目，该项目将利用凯克近红外光谱仪(Keck-NIRSpec)和甚大望远镜低温高分辨率红外回声光谱仪(VLT-CRIRES)来研究原行星盘中气体的性质和演化。年轻恒星周围的恒星圆盘是恒星形成和(地外)行星科学之间的关键纽带。这些圆盘的物理和化学结构，以及它们的传输特性和演化时间，在决定可以形成什么样的行星系统(如果有的话)方面发挥了核心作用。尤其需要对内部几十个天文单位(AU)(行星形成区)的气体进行探测，以区分相互竞争的行星形成模型。虽然在这些地区对气体的直接成像还需要几年的时间，但红外光谱和光谱天体测量学提供了另一条途径。布莱克博士和其他人最近已经证明，来自4.7微米附近的一氧化碳的基本振转发射提供了一个广泛可观察到的诊断气体的方法，该气体位于恒星周盘的0.5-50AU区域。作为这项提议的一部分，将开发的辐射传输工具将使整个天文学社区受益。这一研究项目的结果将指导下一代微波/太赫兹和红外望远镜的观测，并应能够建立详细和定量的环星盘行星形成区域模型。该计划还将推动地面红外光谱和光谱天体测量学达到极限，并将需要优化数据采集、校准和还原例程，以实现接近光子统计所规定的动态范围。这样的例程将用于广泛的观测计划，包括红外径向速度努力和从凌日测量的太阳系外行星大气的特征。作为这项研究计划的一部分，至少四名研究生和几名本科生将以一种特殊的跨学科方式接受培训。布莱克博士的团队还高度参与了加州理工大学早期教育发展科学计划和加州理工大学预科科学倡议K-12教育项目，并正在为各种年级开发新的教学模块。

Dr. Geoffrey Blake (Calfornia Institute of Technology) will lead a collaborative research program with researchers at Leiden University that will utilize the Keck Near Infrared Spectrometer (Keck-NIRSPEC) and the Very Large Telescope Cryogenic High-Resolution Infrared Echelle Spectrograph (VLT-CRIRES) to study the properties and evolution of the gas in protoplanetary disks. Circumstellar disks around young stars provide the pivotal link between star formation and (exo)-planetary science. The physical and chemical structures of these disks, along with their transport properties and evolutionary timescales, play a central role in determining what sort of planetary system, if any, can be formed. Probes of the gas in the inner few tens of Astronomical Units (AU) (the planet-building zone) are particularly needed to distinguish between competing planetary formation models. While the direct imaging of the gas in such regions lies several years into the future, infrared spectroscopy and spectro-astrometry provide an alternative route. Dr. Blake, and others, have recently shown that the fundamental rovibrational emission from carbon monoxide near 4.7 µm provides a widely observable diagnostic of the gas in the 0.5-50 AU region of circumstellar disks.The radiative transfer tools to be developed as part of this proposal will benefit the entire astronomical community. The results of this research project will guide observations with the next generation of microwave/THz and infrared telescopes, and should enable detailed and quantitative models to be constructed of the planet-forming regions of circumstellar disks. This program will also push ground-based infrared spectroscopy and spectro-astrometry to their limits, and will require the optimization of data acquisition, calibration, and reduction routines to achieve a dynamic range close to that imposed by photon statistics. Such routines will be of use to a wide range of observational programs, including infrared radial velocity efforts and the characterization of extrasolar planetary atmospheres from transit measurements. At least four graduate students and several undergraduates will be trained in an exceptionally interdisciplinary manner as part of this research program. Dr. Blake's group is also highly involved in the Caltech Science for Early Educational Development and The Caltech Precollege Science Initiative K-12 educational programs, and is developing new teaching modules for a variety of grade levels.