海冰作为Hycean和海洋世界生命起源的位置
Sea Ice as an Origin of Life Location for Hycean and Ocean Worlds
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中文总结 AI 辅助
本文提出深层海洋行星的海冰-海洋界面可浓缩营养物质，通过三维环流模型和冰过程分析，论证其为非生物起源提供可行位置，拓展了宜居性评估视角。
中文摘要 AI 辅助
具有潜在深层海洋的水世界是目前可观测系外行星宜居性研究的前沿。宜居性的标准要求是存在能源、营养来源和溶剂，这些条件在拥有深层液态水海洋的系外行星上都可以满足。这类行星可能数量众多，范围从hycean世界和海洋世界到含水量增加的类地大小行星。然而，非生物起源需要额外的条件，即一种将营养物质积累到前生物化学所需高浓度的机制，以及驱动化学反应的能源。传统上认为，深层海洋，在某些情况下其下方的高压冰层，会阻止所需浓度的形成。在此，我们概述了一个营养物质可以被浓缩到足够高浓度从而使非生物起源成为可能的位置——开阔海洋与表面冰架之间的界面。利用三维环流模型，我们探索了对应于几颗可能具有昼侧海冰的候选宜居系外行星的情况。我们讨论了行星气候如何影响海冰的性质和行为。我们研究了小规模冰形成和融化过程将营养物质浓缩到前生物有用水平的能力，并探讨了陨石撞击碎片为前生物化学提供平台的潜力。我们发现，这两种机制都可能合理地提供用于前生物化学的浓缩化学原料，这为评估深层海洋行星的宜居性前景增添了重要的新视角。
英文摘要
Water worlds with potential deep oceans are at the forefront of currently observable exoplanetary habitability. The standard requirements for habitability are the presence of an energy source, a source of nutrients, and a solvent, all of which can be met in exoplanets with deep liquid water oceans. Such planets may be numerous, ranging from hycean worlds and ocean worlds to terrestrial-size planets with enhanced water content. However, abiogenesis requires additional conditions, namely a mechanism to accumulate nutrients to the high concentrations required for prebiotic chemistry, and an energy source to drive the chemistry. A deep ocean, and in some cases the high-pressure ice layers underneath, has traditionally been thought to prevent the required concentrations. Here we outline a location where nutrients could be concentrated in sufficiently high quantities to make abiogenesis possible -- at the interface between the open ocean and the surface ice shelf. Using a 3D General Circulation Model, we explore cases corresponding to several candidate habitable exoplanets which might have dayside sea ice. We discuss how the planet's climate influences the nature and behaviour of the sea ice. We investigate the ability of small-scale ice formation and melting processes to concentrate nutrients to prebiotically useful levels, and also explore the potential for meteoritic impactor fragments to provide a platform for prebiotic chemistry. We find that both of these mechanisms may plausibly provide concentrated chemical feedstock for prebiotic chemistry, which adds an important new perspective when evaluating the prospects of habitability in planets with deep oceans.
发表机构
- Institute of Astronomy, University of Cambridge（剑桥大学天文研究所）
- Imperial Astrophysics, Department of Physics, Imperial College London（帝国理工学院物理系天体物理学）
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