Cloudbusting with JWST: characterising aerosols, aurorae and chemistry in substellar atmospheresto the water cloud regime

使用 JWST 进行云消除：描述水云状态下恒星大气中的气溶胶、极光和化学成分

• 批准号: ST/X001091/1
• 负责人: Ben Burningham
• 金额: $ 41.37万
• 依托单位: University of Hertfordshire
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FX001091%2F1
• 关键词: Cloudbusting; JWST; characterising; aerosols; aurorae

JWST will revolutionise the study of alien worlds via its sensitivity to the wavelengths where most of their heat escapes into space - wavelengths of light that cannot be observed easily from the ground. One of the most important groups of planets that JWST will target are giant planets, similar to Jupiter, that orbit other stars. These worlds are important for understanding how planetary systems form and evolve because they represent most of the mass in their planetary systems, in the same way that Jupiter dominates our own Solar system. And, like Jupiter, giant exoplanets are thought to play an important role in delivering water to rocky, possibly habitable, planets in their systems. Giant planets are also the easiest planets to observe outside the Solar System, so they also provide a testing ground for enhancing our ability to study all kinds of exoplanets, even potentially habitable ones. One of the most challenging problems in studying exoplanets is how to deal with clouds. Clouds block our view, and also change the composition and other properties of alien atmospheres in complicated and difficult to measure ways. Because of this, clouds are often seen as an obstacle to exoplanet science. However, thanks to JWST and the analysis tools that we have developed, clouds will soon be able provide new insights into the composition, chemistry and dynamics of alien worlds. Alongside clouds, powerful aurorae have been discovered on free floating Jupiter-like worlds known as brown dwarfs, and we expect to find similar aurorae on giant exoplanets in the future. Interestingly, all the brown dwarfs that show aurorae also show variations in their brightness as they rotate. Such variability has been seen in many other brown dwarfs and even some giant exoplanets, and it is generally thought to be due to weather creating bright and dark patches due to differing cloud cover. It is also possible that some of the variability is driven by aurorae, or even that weather, and associated large scale atmospheric flows, may interact with the aurorae in ways yet to be discovered. With this funding, we will learn how to decode JWST spectra of distant worlds to reveal their cloud properties, composition, and thermal structure, and understand how their aurorae interact with their atmospheres. We will also use JWST to study some of the coolest brown dwarfs known, called Y dwarfs. Y dwarfs are cool enough to have water ice clouds in their atmospheres. These will be the first studies of water clouds beyond the Solar system. Thanks to prior knowledge of the compositions of some of these brown dwarfs, we will be able to calibrate our understanding of clouds, and then use this knowledge to study giant planets. We will also be able to test different theories of cloud formation and chemistry, as well as study the weather on these alien worlds. This work will develop techniques that we will need in order study all kinds of cloudy exoplanets. It will also pave the way for robust estimates of the composition of giant exoplanets - an essential piece of evidence for revealing their formation histories and that of their home planetary systems.

詹姆斯韦伯太空望远镜将通过其对大部分热量逃逸到太空的波长（从地面无法轻易观察到的光波长）的敏感性，彻底改变对外星世界的研究。詹姆斯韦伯太空望远镜将瞄准的最重要的行星群之一是围绕其他恒星运行的巨行星，类似于木星。这些世界对于理解行星系统如何形成和演化非常重要，因为它们代表了行星系统中的大部分质量，就像木星主宰我们太阳系一样。而且，像木星一样，巨型系外行星被认为在向其系统中的岩石行星（可能适合居住）输送水方面发挥着重要作用。巨行星也是太阳系外最容易观测到的行星，因此它们也为增强我们研究各种系外行星，甚至是潜在宜居行星的能力提供了一个试验场。研究系外行星最具挑战性的问题之一是如何处理云。云阻挡了我们的视线，还以复杂且难以测量的方式改变了外星大气的成分和其他特性。正因为如此，云常常被视为系外行星科学的障碍。然而，借助 JWST 和我们开发的分析工具，云很快就能提供关于外星世界的组成、化学和动力学的新见解。除了云层之外，在被称为褐矮星的自由漂浮的类木星世界上也发现了强大的极光，我们预计将来会在巨大的系外行星上发现类似的极光。有趣的是，所有显示极光的褐矮星在旋转时也会显示出亮度的变化。这种变化在许多其他褐矮星甚至一些巨大的系外行星中也出现过，人们普遍认为这是由于不同的云层覆盖造成的天气造成的亮斑和暗斑造成的。某些变化也可能是由极光驱动的，甚至天气和相关的大规模大气流动可能以尚未发现的方式与极光相互作用。借助这笔资金，我们将学习如何解码遥远世界的 JWST 光谱，以揭示它们的云特性、成分和热结构，并了解它们的极光如何与大气相互作用。我们还将使用 JWST 来研究一些已知最冷的棕矮星，称为 Y 矮星。 Y型矮星的温度足够低，其大气层中存在水冰云。这将是对太阳系以外水云的首次研究。由于事先了解了其中一些褐矮星的成分，我们将能够校准我们对云的理解，然后利用这些知识来研究巨行星。我们还将能够测试不同的云形成和化学理论，并研究这些外星世界的天气。这项工作将开发我们研究各种云状系外行星所需的技术。它还将为对巨型系外行星的组成进行可靠的估计铺平道路——这是揭示其形成历史及其母行星系统形成历史的重要证据。

项目成果

Predicting Cloud Conditions in Substellar Mass Objects Using Ultracool Dwarf Companions

使用超冷矮星伴星预测亚恒星质量天体中的云状况

• DOI: http://dx.10.3847/1538-4357/ad1f6d
• 发表时间: 2024
• 期刊: The Astrophysical Journal
• 作者: Calamari E