Interior-atmosphere feedbacks and the nature of detected sub-Neptunian planets

内部大气反馈和探测到的海王星以下行星的性质

• 批准号: 362466810
• 负责人: Professorin Dr. Heike Rauer, since 7/2020
• 金额: --
• 依托单位: Institut für Planetenforschung
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/362466810?language=en
• 关键词: Interior; atmosphere; feedbacks; nature; detected

The relatively young research field of extrasolar planets has revealed an unexpectedly large diversity of planets, which could not be foreseen from studies of the Solar System. After the astonishing discovery of Hot Jupiters, which can not be formed where they are observed, the finding that no clear division into rocky and gaseous planets is realized, has revolutionized our understanding of planetary formation and evolution. The rather continuous transition between rocky and gaseous planets is found in the sub-Neptunian mass and radius regime (M<20M_Earth and R<4R_Earth), and was identified by independent measurements of planetary radius and mass. The resulting mean density of planets in these regime can be accounted for in terms of a variety of interior structures based on an iron core, a rocky mantle, possibly an ice layer, and a more or less thick atmosphere, all of them in proportions that are difficult to constrain. The atmospheres of these planets may have different origins, such as accretion from the protoplanetary disc, sublimation of accreted ices, or outgassing from the interior. In this project, we aim at understanding for which detected planets in the sub-Neptunian mass-radius regime secondary outgassing from rocky interiors due to mantle melting and volcanism is in principle possible. Furthermore, we are interested in understanding how large the impact of interior-atmosphere feedbacks due to the outgassing and subsequent changes in the atmospheric conditions and escape may be on the measured planetary radius. We will expand models of interior structure, thermal and outgassing evolution, as well as atmosphere models and apply them to observed planets in the sub-Neptunian mass-radius regime. The inferred interior structures will build the starting point of investigations of the interior thermal evolution and potential outgassing, as well as of the atmospheric temperature and composition. We expect that outgassing from the interior, of CO2 in particular, may lead to important changes in the atmospheric mass, composition and, in turn, also atmospheric temperatures. Together with collaboration partners, we will explore whether these modeled atmospheres are subject to strong atmospheric escape, and under which circumstances CO2-outgassing may alter the loss processes. The feedback of the atmospheric temperature and mass upon the interior evolution will be finally considered by building a coupled interior-atmosphere model.The results of these detailed model calculations of the planetary interior and atmosphere will be compared to the initial results of the interior structure modelling to show under which conditions these processes may substantially modify the apparent planetary radius. This may allow us to rule out certain solutions derived from interior structure models alone and to put additional constraints on the nature of the investigated bodies.

相对年轻的太阳系外行星研究领域已经揭示了行星的意外大多样性，这是从太阳系的研究中无法预见的。在惊人地发现了热行星之后，它们不能在被观察到的地方形成，发现没有明确的岩石和气体行星的划分，彻底改变了我们对行星形成和演化的理解。在亚海王星质量和半径区域（M<20M_Earth和R<4R_Earth），岩石行星和气态行星之间的过渡相当连续，并通过对行星半径和质量的独立测量来确定。在这些状态下，行星的平均密度可以用各种内部结构来解释，这些内部结构基于铁的核心，岩石地幔，可能是冰层，以及或多或少厚的大气层，所有这些都很难限制。这些行星的大气层可能有不同的来源，例如来自原行星盘的吸积，吸积冰的升华，或来自内部的释气。在这个项目中，我们的目标是了解在亚海王星质量半径制度检测到的行星二次放气从岩石内部由于地幔熔融和火山活动在原则上是可能的。此外，我们感兴趣的是了解有多大的影响走廊大气反馈，由于放气和随后的变化，在大气条件和逃逸可能对测量的行星半径。我们将扩展内部结构，热和放气演化模型，以及大气模型，并将其应用于亚海王星质量半径制度中观察到的行星。推断的内部结构将建立内部热演化和潜在的放气，以及大气温度和成分的调查的起点。我们预计，从内部释放的气体，特别是CO2，可能会导致大气质量，成分的重要变化，反过来，大气温度也会发生变化。与合作伙伴一起，我们将探索这些模拟的大气是否会受到强烈的大气逃逸，以及在何种情况下CO2释气可能会改变损失过程。最后将通过建立一个行星-大气耦合模型来考虑大气温度和质量对行星内部演化的反馈作用，并将这些行星内部和大气的详细模型计算结果与内部结构模型的初始结果进行比较，以显示在何种条件下这些过程可能会大大改变行星的视半径。这可能使我们能够排除某些解决方案来自内部结构模型单独和把额外的约束的性质的调查机构。