岩浆世界K2-141 b的地幔对流与夜侧火山活动
Mantle Convection and Nightside Volcanism on Lava World K2-141 b
AI总结：
本研究通过二维对流模型探讨了岩浆世界K2-141 b的地幔动态、夜侧火山活动及挥发物逸出，发现火山活动可释放大量CO₂和H₂O，并分析了其热辐射信号对观测的影响。
摘要：
超短周期的岩浆世界为研究极端辐射下行星内部和大气的耦合演化提供了独特窗口。本研究利用基于示踪剂的挥发物追踪方法，通过二维对流模型，探讨了岩浆世界K2-141 b（1.54 R_⊕，5.31 M_⊕）的地幔动态、夜侧火山活动和挥发物逸出。我们的模拟探索了多种内部配置，包括有无塑性屈服、基底与混合加热、核心冷却和岩浆侵入等模型。在无塑性屈服（即强地壳）模型中，我们发现地幔上涌形成于恒星点和反恒星点，而下涌形成于昼夜分界线，位于熔融海洋与冷固态夜侧之间。这些下涌促进了地壳物质的循环，代表了一种不对称、单壳层构造活动。所形成的熔融海洋厚度根据模型参数变化，从200到300公里，对应于约行星半径的2-3%。持续的夜侧火山活动形成玄武岩地壳，并逐渐耗尽地幔中的挥发物。我们发现，经过十亿年，火山喷发可释放数十个巴的CO₂和H₂O。我们表明，即使较大的夜侧火山喷发产生的热辐射信号也不超过1 ppm，仍低于热相变曲线的当前检测阈值。然而，对于大多数模型，逸出率在昼夜分界线附近增加，未来研究应评估这种局部逸出是否会导致传输光谱中的大气特征。
英文摘要：
Ultra-short period lava worlds offer a unique window into the coupled evolution of planetary interior and atmospheres under extreme irradiation. In this study, we investigate the mantle dynamics, nightside volcanism, and volatile outgassing on lava world K2-141 b ($1.54 R_{\oplus}$, $5.31 M_{\oplus}$) using two-dimensional convection models with tracer-based volatile tracking. Our simulations explore a range of interior configurations, including models with and without plastic yielding, basal versus mixed heating, core cooling, and melt intrusion. In models without plastic yielding (i.e. with a strong lithosphere), we find that mantle upwellings form at the substellar and antistellar points, while downwellings form near the day-night terminators at the boundary between the magma ocean and cold, solid nightside. These downwellings facilitate the recycling of crustal material, representing a form of asymmetric, single-lid tectonics. The resulting magma ocean thickness varies from 200 to 300 km depending on the model parameters, corresponding to about 2-3% of the planet's radius. Continuous nightside volcanism produces a basaltic crust and gradually depletes the mantle of volatiles. We find that over a billion years, volcanic eruptions can outgas tens of bars of CO$_{2}$ and H$_{2}$O. We show that even relatively large volcanic eruptions on the nightside produce thermal emission signals of no more than 1 ppm, remaining below the current detectability threshold in thermal phase curves. However, for most models, outgassing rates are increased near the day-night terminators and future studies should assess whether such localised outgassing could lead to atmospheric signatures in transmission spectroscopy.
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