Exploring the atmospheres of the Giant Planets with James Webb

詹姆斯·韦伯太空望远镜(JWST)计划在博士项目开始之际发射，它将彻底改变我们对太阳系内外行星大气的理解。其直径6.5米的屏蔽镜，结合最先进的红外仪器，将提供对太阳系目标的精细观测。莱斯特大学的研究人员直接参与了MIRI仪器的开发(中红外光谱为5-30微米)，莱斯特行星科学家有机会获得所有四颗巨行星的保证时间观测，这些观测将在运行的第一年(2021-22年)获得。这位博士候选人将受到莱斯特行星大气研究小组的欢迎，他们将接受红外光谱逆变换的培训，以提取关于温度、化学分布、云和大气动力学的有用信息。学生将使用一套完善的辐射传输和光谱反演工具(称为复仇女神)，将之前航天器对木星和土星的观测与来自JWST的备受期待的新数据进行比较。气体的空间分布将允许学生自由地探索各种科学问题：(I)关键元素丰度和同位素比率的比率，以限制行星的起源；(Ii)使用可凝聚挥发物(如氨)和不平衡物种(如磷化氢)来跟踪大气动力学的变化(例如，带和带，以及大型结构，如木星的大红斑和土星的极六边形)；以及(Iii)木星天气与巨型行星化学丰富的中间大气的耦合。通过这些学习，学生将获得处理和操作航天器数据的技能，广泛的软件开发，并将有机会与全球更广泛的行星观察者社区接触。JWST观测将辅之以一系列来自世界领先设施(如智利和夏威夷的天文台)的地面辅助观测活动。考虑到JWST任务涉及的风险，这项研究仍然可以利用现有的航天器数据(主要来自卡西尼号和朱诺号)，并辅之以我们正在进行的地面行星天文计划。随着莱斯特目前参与JUNO和JWST，以及未来参与木星冰冷卫星探测器(UUCE)，这个行星科学博士项目提供了在巨型行星上做出令人兴奋的新发现的可能性。成功的博士候选人应具有一定的编程背景，因为他们将在莱斯特的高性能计算设施上使用Fortran、IDL和基于Python的包。对行星大气科学和辐射传输有一定的先验知识是可取的。

The James Webb Space Telescope (JWST), scheduled for launch near the start of this PhD programme, is set to revolutionise our understanding of planetary atmospheres in this Solar System and beyond. Its 6.5-m diameter shielded mirror, combined with state-of-the-art infrared instrumentation, will provide exquisite observations of Solar System targets. Researchers at the University of Leicester were directly involved in the development of the MIRI instrument (5-30 micron spectroscopy in the mid-infrared), and Leicester planetary scientists have unique access to guaranteed-time observations of all four giant planets, to be acquired during the first year of operations (2021-22). The PhD candidate would be welcomed to a team of planetary atmospheres researchers at Leicester, to be trained in inversions of infrared spectroscopy to extract useful information on temperatures, chemical distributions, clouds, and atmospheric dynamics. The student will use a well-developed suite of radiative transfer and spectral inversion tools (known as NEMESIS) to compare previous spacecraft observations of Jupiter and Saturn to the highly-anticipated new data from JWST. The spatial distributions of gases will allow the student freedom to pursue a variety of scientific questions: (i) the ratios of key elemental abundances and isotope ratios to constrain planetary origins; (ii) the use of condensable volatiles (like ammonia) and disequilibrium species (like phosphine) to track changes in atmospheric dynamics (e.g., belts and zones, and large-scale structures like Jupiter's Great Red Spot and Saturn's polar hexagon); and (iii) the coupling of jovian weather with the chemically-rich middle atmospheres of the giant planets. Through these studies, the student will gain skills in processing and manipulating spacecraft data, extensive software development, and will have the opportunity to engage with the wider community of planetary observers across the globe. JWST observations will be supplemented by a campaign of ground-based supporting observations from world-leading facilities (e.g., observatories in Chile and Hawaii). Given the risks involved with the JWST mission, this studentship can still be undertaken with existing spacecraft data (primarily from Cassini and Juno), supplemented by our ongoing programme of ground-based planetary astronomy.With Leicester's current involvement in Juno and JWST, and future involvement in the Jupiter Icy Moons Explorer (JUICE), this Planetary Science PhD project offers the potential for exciting new discoveries on the giant planets. Successful PhD candidates would have some prior background in coding, as they will be using Fortran, IDL, and Python-based packages on Leicester's High-Performance Computing facility. Some prior knowledge of planetary atmospheric science and radiative transfer is desirable.