亚海王星系外行星通常被假设由富含硅酸盐的岩浆洋和覆盖其上的富氢大气组成。先前关于硅酸盐物质释气的研究表明,这种大气与内部的相互作用会影响大气的整体结构和范围。但这些模型仅考虑了氢气大气中的 SiO,并未考虑它们之间的化学反应。在此,我们将 H、Si 和 O 物种之间的化学平衡计算与大气结构模型相耦合。我们发现,富硅酸盐内部与富氢大气的相互作用会产生大量的硅烷(SiH$_4$)和水(H$_2$O)。这些物质可延伸至大气高层,尽管其丰度在温度最高、最深的区域达到最大。例如,对于一颗质量为 4 $M_\oplus$、平衡温度为 1000 K、底部温度为 5000 K且拥有 0.1 $M_\oplus$ 氢包层的行星,硅物种和水按数量可占大气底部的 30%。由于这种丰度增强,我们发现温度 $\gtrsim 2500$ K 时对流受到抑制。该温度低于以往未考虑大气化学的模型所预测的温度,这意味着由此产生的非对流区域更厚。我们的研究结果表明,仅通过岩浆与氢的相互作用就能产生大量的内源水,而无需吸积富冰物质。我们讨论了大气与内部相互作用特征的可观测性以及未来的工作方向,包括凝结物悬浮和更复杂的化学网络。
英文摘要:
Sub-Neptune exoplanets are commonly hypothesized to consist of a silicate-rich magma ocean topped by a hydrogen-rich atmosphere. Previous work studying the outgassing of silicate material has demonstrated that such atmosphere-interior interactions can affect the atmosphere's overall structure and extent. But these models only considered SiO in an atmosphere of hydrogen gas, without considering chemical reactions between them. Here we couple calculations of the chemical equilibrium between H, Si, and O species with an atmospheric structure model. We find that substantial amounts of silane, SiH$_4$, and water, H$_2$O, are produced by the interaction between the silicate-rich interior and hydrogen-rich atmosphere. These species extend high into the atmosphere, though their abundance is greatest at the hottest, deepest regions. For example, for a 4 $M_\oplus$ planet with an equilibrium temperature of 1000 K, a base temperature of 5000 K, and a 0.1 $M_\oplus$ hydrogen envelope, silicon species and water can comprise 30 percent of the atmosphere by number at the bottom of the atmosphere. Due to this abundance enhancement, we find that convection is inhibited at temperatures $\gtrsim 2500$ K. This temperature is lower, implying that the resultant non-convective region is thicker, than was found in previous models which did not account for atmospheric chemistry. Our findings show that significant endogenous water is produced by magma-hydrogen interactions alone, without the need to accrete ice-rich material. We discuss the observability of the signatures of atmosphere-interior interaction and directions for future work, including condensate lofting and more complex chemical networks.
Three-dimensional transport-induced chemistry on temperate sub-Neptune K2-18b, Part II: the combined effects of atmospheric dynamics and chemical reactions
Max Planck Institute for Astronomy(马克斯·普朗克天文学研究所);Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University(北京大学物理学院大气与海洋科学系);Department of Physics and Astronomy, Faculty of Environment, Science and Economy, University of Exeter(埃克塞特大学环境、科学与经济学院物理与天文系)
The Formation of Uranus and Neptune in Solid-Rich Feeding Zones: Connecting Chemistry and Dynamics
行星形成的核心吸积理论至少有两个基本问题来解释天王星和海王星的起源:(1)跨土星太阳星云的动力学时间很长,核心的增长可能需要超过1500万年,(2)当核心达到10个地球质量时,失控的气体吸积开始发生,这就需要在冰巨人核心达到临界质量时突然停止气体吸积。这两个问题都可以通过允许冰巨星在富含固体的供给区形成后向外迁移来解决,这些供给区的星子表面密度远高于最小质量的太阳星云。我们使用Nice模型(Gomes et al. 2005; Morbidelli et al. 2005; Tsiganis et al. 2005)的初始半长轴分布,对Dodson-Robinson et al.(2009)的富固体盘中天王星和海王星的形成进行了新的模拟,其中一个冰巨星在12 AU形成,另一个在15 AU形成。最里面的冰巨星在380万~ 400万年后达到现在的质量,最外面的冰巨星在530万~ 600万年后达到现在的质量,与以前的一维模拟相比,时间缩短了很多(例如Pollack et al. 1996)。核心质量保持亚临界状态,消除了突然停止气体吸积的需要。我们计算的碳质量分数为22%,与Podolak等人(1995)和Marley等人(1995)的冰巨星内部模型非常一致。基于形成冰巨星的微行星含有>10%质量分数的甲烷冰的要求,我们可以拒绝任何最初将天王星和海王星置于土星轨道内的太阳系形成模型。我们…
Contrasting C/O ratios in Uranus and Neptune from disequilibrium chemistry: A clue to distinct evolutionary pathways?
Aix-Marseille Université(艾克斯-马赛大学);Southwest Research Institute(西南研究院);Laboratoire d’Astrophysique de Bordeaux, Univ. Bordeaux(波尔多大学天体物理实验室);Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université Paris Cité(巴黎天文台、巴黎文理研究大学、法国国家科学研究中心、索邦大学、巴黎西岱大学);University of Science and Technology of China(中国科学技术大学);Dublin Institute for Advanced Studies(都柏林高等研究所);Space Science Institute(空间科学研究所)
Chemistry of Temperate Super-Earth and Mini-Neptune Atmospheric Hazes from Laboratory Experiments
很少有实验工作来探索在与外太阳系或早期地球的大气成分或温度非常不同的大气中形成的光化学烟雾的性质。随着太阳系外行星的发现数量达到数千,这个未开发的相空间值得探索。这项研究提出了测量的化学性质的烟雾颗粒产生的实验室模拟系外行星大气。我们使用甚高分辨率质谱仪测量大气室实验中产生的固体颗粒的化学成分。检测到许多复杂的分子种类,其化学通式为C $_w$ H $_x$ N $_y$ O $_z$。我们检测的数据,包括单糖甘油醛,各种氨基酸和核苷酸碱基,和几个糖衍生物的分子式的益生元的利益。此外,实验性的系外行星霾类似物表现出不同的溶解度特性,这为进一步了解超级地球和迷你海王星大气中光化学霾的化学或物理变化的可能性提供了见解。这些系外行星模拟粒子可以帮助我们更好地了解化学大气过程,并提出遥远世界原位大气生物前化学的可能来源。
Host--Non-host Differences in Stellar Chemistry, Activity, and Birth Radius: Hints of Distinct Formation Environments for Earth-like Planets and Sub-Neptunes
School of Science, Hangzhou Dianzi University(杭州电子科技大学理学院);National Astronomical Data Center Zhijiang Branch(国家天文台数据科学中心(紫金山));CAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences(中国科学院国家天文台光学天文重点实验室);Department of Astronomy, The Ohio State University(俄亥俄州立大学天文学系);Center for Cosmology and Astroparticle Physics (CCAPP), The Ohio State University(俄亥俄州立大学宇宙学与高能物理中心);Department of Physics, Xiangtan University(湘潭大学物理系);School of Physics and Astronomy, Beijing Normal University(北京师范大学物理与天文学院)
The Role of Intrinsic Temperature and Vertical Mixing in Characterizing Sub-Neptune Atmospheres
The Pennsylvania State University(宾夕法尼亚州立大学);Southeastern Universities Research Association(东南部大学研究协会);NASA Goddard Space Flight Center(美国宇航局戈达德太空飞行中心);NASA Ames Research Center(美国宇航局艾姆斯研究中心);University of Washington(华盛顿大学);Arizona State University(亚利桑那州立大学)
Magma ocean interactions can explain JWST observations of the sub-Neptune TOI-270 d
School of Earth and Space Exploration, Arizona State University(亚利桑那州立大学地球与空间探索学院);Department of Astronomy, University of Maryland(马里兰大学天文学系);Space Telescope Science Institute(太空望远镜科学研究所);Department of Astronomy & Astrophysics, University of Chicago(芝加哥大学天文学与天体物理学系);Kapteyn Astronomical Institute, University of Groningen(格罗宁根大学卡普坦天文研究所);Earth and Planets Laboratory, Carnegie Institution for Science(卡内基科学学会地球与行星实验室)
Cool, Cloudy Nights on an Ultrahot Neptune: A Panchromatic NIRISS/NIRSpec Transmission Spectrum of LTT 9779 b
University of New Mexico(新墨西哥大学);Space Telescope Science Institute(太空望远镜科学研究所);Johns Hopkins University Applied Physics Laboratory(约翰斯·霍普金斯大学应用物理实验室);University of Kansas(堪萨斯大学);University of Maryland(马里兰大学);Universite Cote d’Azur(蔚蓝海岸大学)
Impact of Clouds on the Atmosphere-Mantle Interface of Sub-Neptunes
School of Earth and Space Exploration, Arizona State University(亚利桑那州立大学地球与空间探索学院);Department of Astronomy, University of Texas at Austin(德克萨斯大学奥斯汀分校天文学系);NASA Ames Research Center(NASA艾姆斯研究中心);SETI Institute(SETI研究所)
Chemical equilibrium between Cores, Mantles, and Atmospheres of Super-Earths and Sub-Neptunes, and Implications for their Compositions, Interiors and Evolution
Quantified Estimation of Molecular Detections across Different Classes of Neptunian Atmospheres Using Cross-Correlation Spectroscopy: Prospects for Future Extremely Large Telescopes with High-Resolution Spectrographs
Hydrocarbon Hazes on Temperate sub-Neptune K2-18b supported by data from the James Webb Space Telescope
University College London(伦敦大学学院);Universite de Reims Champagne Ardenne(兰斯香槟阿登大学);King’s College London(伦敦国王学院);Osservatorio Astronomico di Palermo(巴勒莫天文台)
The Role of Formation Location in Shaping Sulfur-, Nitrogen-, and Carbon-Bearing Species in Super-Earth and Sub-Neptune Atmospheres
Institute for Particle Physics and Astrophysics, ETH Zurich(苏黎世联邦理工学院粒子物理与天体物理研究所);Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles(加州大学洛杉矶分校地球、行星与空间科学系);Observatoire de la Côte d’Azur, Université Cote d’Azur, Laboratoire Lagrange(蔚蓝海岸天文台,尼斯大学,拉格朗日实验室);Department of Space Research and Technology, Technical University of Denmark(丹麦技术大学太空研究与技术系)
Hot and cloudy: High temperature clouds in super-Earths and sub-Neptunes
Leiden Observatory(莱顿天文台);SRON Netherlands Institute for Space Research(荷兰空间研究所);Tsinghua University(清华大学);Jet Propulsion Laboratory, California Institute of Technology(加州理工学院喷气推进实验室)
Understanding the chemistry of temperate exoplanets atmospheres through experimental and numerical simulations
UVSQ Université Paris-Saclay, Sorbonne Université, CNRS(凡尔赛大学巴黎萨克雷大学、索邦大学、法国国家科学研究中心);ETH University, Center for Origin and Prevalence of Life, Department of Earth and Planetary Sciences(苏黎世联邦理工学院,生命起源与普遍性中心,地球与行星科学系);ENS-Paris-Saclay(巴黎萨克雷高等师范学校)
Beyond Equilibrium Temperature: How the Atmosphere/Interior Connection Affects the Onset of Methane, Ammonia, and Clouds in Warm Transiting Giant Planets