Collaborative Research: Revealing Exoplanet Atmospheres Using High-Resolution Spectroscopy

由芝加哥大学和亚利桑那州立大学领导的一个团队将实施一个观测项目，以帮助回答关于围绕遥远恒星运行的近距离巨型行星的大气的四个科学问题：化学丰度如何追踪行星的起源？大气温度如何依赖于外部辐射、重力和成分？行星的动力学和磁场是如何控制风速的？在化学转变过程中，大气的性质是什么？该团队将通过研讨会培训科学界使用探测行星大气的新技术。讲习班将侧重于早期职业研究人员，并将通过向代表性不足群体的初级科学家提供资金支持来扩大参与范围。使用互相关技术的地面高分辨率光谱学是探测系外行星大气的一种强大但复杂的方法。项目组开发了一种互相关光谱学的大气反演方法，能够提取对化学成分的详细限制条件。该团队将把这项技术应用于最先进的高分辨率数据集，以测量碳氧丰度比、大气金属丰度、碳同位素丰度、难熔物质丰度，以及大气温度如何随压力变化。该团队将使用三台最灵敏的高分辨率光谱仪进行调查：双子座南部的IGRINS，双子座北部的Maroon-X，以及VLT上的浓缩咖啡。这些仪器跨越了从光学到近红外的范围，提供了各种原子和分子物种中主要耐火(Fe、Ti、V)和挥发性(C、N、O)元素及其同位素(C、Ti)的光谱线。这些调查将利用透射式和相分辨热发射测量，以30多个具有广泛物理参数的行星为目标。工作坊学员将学习如何准备观测数据，以及如何对高分辨率数据进行端到端的完整还原和分析。研讨会的讲座将被记录下来并发布在网上，一套数据分析和大气恢复软件将公开提供。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

A team led by the University of Chicago and Arizona State University will carry out an observational program to help answer four science questions regarding the atmospheres of close-in giant planets orbiting distant stars: How do chemical abundances trace planet origins? How does atmosphere temperature depend on external radiation, gravity, and composition? How do the dynamic and magnetic fields of planets govern wind speeds? And what are atmosphere properties across chemical transitions? The team will train the science community in the use of new techniques for probing planet atmospheres with workshops. Workshops will focus upon early career researchers and will broaden participation by providing monetary support for junior scientists from underrepresented groups. Ground-based, high-resolution spectroscopy using the cross-correlation technique is a powerful, but complex method for probing exoplanet atmospheres. The project team have developed an atmospheric retrieval approach for cross-correlation spectroscopy which enables the extraction of detailed constraints on chemical compositions. The team will apply this technique to state-of-the-art high-resolution datasets to measure carbon-to-oxygen abundance ratios, atmospheric metallicity, carbon isotopic abundances, refractory species abundances, and how atmospheric temperature varies with pressure. The team will be carrying out a survey using three of the most sensitive high-resolution spectrographs: IGRINS on Gemini South, MAROON-X on Gemini North, and ESPRESSO on the VLT. These instruments span the optical to the near-infrared, yielding access to spectroscopic lines from major refractory (Fe, Ti, V) and volatile (C, N, O) elements and their isotopologues (C, Ti) in a variety of atomic and molecular species. The surveys will utilize both transmission and phase-resolved thermal emission measurements, targeting more than 30 planets with a broad range of physical parameters. Workshop attendees will be walked through how to prepare observations and the full end-to-end reduction and analysis of high-resolution data. The workshop lectures will be recorded and posted online and a suite of data analysis and atmospheric retrieval software will be made publicly available.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.