Exploring the causes of exoplanetary atmospheric evaporation

探索系外行星大气蒸发的原因

• 批准号: 2008066
• 负责人: Elisabeth Newton
• 金额: $ 36.09万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2008066&HistoricalAwards=false
• 关键词: Exploring; causes; exoplanetary; atmospheric; evaporation

One of the key determining factors for exoplanet habitability is the condition of its atmosphere. It then becomes important to understand the mass loss mechanisms that might affect exoplanets after their formation and through their evolution. This work will be to develop models of this mechanism. The team will adapt an existing model to three similar transiting planets which orbit similar stars. Two of the three planets show evidence of atmospheric evaporation in their transits, but the third planet does not. These three worlds, so similar but yet with such different results for atmospheric evaporation, might provide a unique insight into planetary evolution. This work will support a graduate student and will support four female undergraduate interns. Part of the internships will include participation in a workshop on science communication. The PI will also conduct outreach by participating in the Dartmouth Foreign Studies Program in South Africa.The team will adapt the Evaporating Exoplanet code (EVE) by including three new phenomena that have not yet been incorporated into the code. They will use the code to produce models of three similar exoplanets around three similar stars: K2-25b, Gl 436b, and GJ 3470b. Of these, K2-25b has not been observed to exhibit atmospheric evaporation, but the other two have. Once these systems have been understood, the team will conduct a parameter study to assess how planetary exospheres are impacted by their stars across a range of stellar and planetary parameters. In particular, the team will explore the efficacy of particle-based models versus hydrodynamic codes for the full 3D stellar wind problem. They will also include pickup protons which result from charge exchange between the planetary exosphere and the stellar wind. Prior models neglected this potential source of particles. They will also explicitly model atmospheric helium, which has not been included in prior models.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.

系外行星可居住性的关键决定因素之一是其大气层的状况。因此，了解可能在系外行星形成后及其演化过程中影响系外行星的质量损失机制变得非常重要。这项工作将是开发这一机制的模型。该团队将调整现有的模型，以适应三个类似的凌日行星，它们围绕类似的恒星运行。三颗行星中有两颗在凌日时显示出大气蒸发的证据，但第三颗行星没有。这三个世界如此相似，但大气蒸发的结果却如此不同，这可能为行星演化提供了独特的见解。这项工作将支持一名研究生，并将支持四名女大学生实习生。部分实习将包括参加科学传播讲习班。PI还将通过参加南非的达特茅斯外国研究项目来开展外联活动。该团队将通过包括三种尚未纳入代码的新现象来调整蒸发系外行星代码（EVE）。他们将使用该代码生成围绕三颗类似恒星的三颗类似系外行星的模型：K2- 25 b，Gl 436 b和GJ 3470 b。其中，K2- 25 b没有观察到大气蒸发，但其他两个有。一旦了解了这些系统，该团队将进行参数研究，以评估行星外太空如何在一系列恒星和行星参数中受到恒星的影响。特别是，该团队将探索基于粒子的模型与流体动力学代码的有效性，以解决完整的3D恒星风问题。它们还将包括行星外逸层和恒星风之间电荷交换产生的拾取质子。先前的模型忽略了这种潜在的粒子源。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。