发表机构
Planétarium de Montréal, Espace pour la Vie; Trottier Institute for Research on Exoplanets, Department of Physics, Université de Montréal; Laboratoire Lagrange, Université de la Côte d’Azur, Observatoire de la Côte d’Azur, CNRS; Johns Hopkins APL; Tsung-Dao Lee Institute & School of Physics and Astronomy, Shanghai Jiao Tong University; Astrophysics & Space Center, Schmidt Sciences; School of Earth and Space Exploration, Arizona State University; Astrophysics, Department of Physics, University of Oxford; Department of Astronomy & Astrophysics, University of California, Santa Cruz; Anton Pannekoek Institute for Astronomy, University of Amsterdam; Department of Astronomy & Astrophysics, University of Chicago（蒙特利尔天文馆，生命空间; 特罗蒂埃系外行星研究所，物理系，蒙特利尔大学; 拉格朗日实验室，蔚蓝海岸大学，蔚蓝海岸天文台，法国国家科学研究中心; 约翰斯·霍普金斯大学应用物理实验室; 汤川秀树研究所与物理天文学院，上海交通大学; 天体物理与太空中心，施密特科学; 地球与太空探索学院，亚利桑那州立大学; 天体物理学，物理系，牛津大学; 天文与天体物理学系，加州大学圣克鲁兹分校; 安东·潘内科克天文学研究所，阿姆斯特丹大学; 天文与天体物理学系，芝加哥大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用JWST对热木星NGTS-10 Ab的首条分离热辐射与反射光的相位曲线，发现其温度与反射率反相关，表明存在不均匀硅酸盐云覆盖，并测得热输运随深度增强的斜率，揭示了环流与云形成的相互作用。
AI 中文摘要
热木星是平衡温度超过1000 K的气态巨行星，其永久白天和夜晚面之间存在巨大的温度梯度，导致其环流模式在太阳系中无对应物。过去的开普勒和斯皮策观测表明，这些天体的相位曲线在光学波长下通常在星下点以西达到峰值，而在红外波段则以东侧为峰值，这指示了环流与云覆盖之间的相互作用。然而，很少有热木星拥有联合的反射光和热辐射测量，这阻碍了对这些现象之间联系的明确论断。在此，我们展示了首条通过JWST对NGTS-10 Ab的NIRSpec PRISM仪器（λ=0.5-5.5 μm）观测将热辐射和反射光分离的热木星相位曲线。利用光谱分辨的相位曲线，我们联合反演了行星的热图和反射光图。我们表明温度与反射率分布呈反相关，最佳解释为云从温度最高的东部星下区域（φ≈-17至48°）蒸发。通过与三维环流模型的相位分辨光谱比较，证实了NGTS-10 Ab的大气存在不均匀的云覆盖，可能由微米级硅酸盐颗粒组成，并且大气阻力较弱（τ_drag>10^6 s）。最后，通过测量热相位曲线偏移的光谱变化，我们推断出每压力十倍的斜率为7.1±1.9度，表明热输运在深处更为高效。未来对广泛平衡温度范围内的热木星进行光学和红外相位曲线测量，将能够完整描绘高辐照系外行星大气中热输运与云形成之间的相互作用。
英文摘要
Hot-Jupiters, gas giant planets with equilibrium temperatures above 1,000 K, host large temperature gradients between their permanent day- and nightsides, resulting in circulation regimes that have no Solar System analogs. Past Kepler and Spitzer measurements show that the phase curves of these objects typically peak westward of the substellar point at optical wavelengths and eastward in the infrared, indicative of an interaction between circulation and cloud coverage. However, few hot-Jupiters have joint reflected light and thermal emission measurements, preventing a definitive statement as to the link between these phenomena. Here, we present the first phase curve of a hot-Jupiter that separates thermal emission and reflected light through JWST observations of NGTS-10 Ab with the NIRSpec PRISM instrument ($λ$=0.5-5.5 $μ$m). Using the spectrally-resolved phase curve, we jointly retrieve the planet's thermal and reflected light maps. We show that the temperature and reflectance distributions are anti-correlated, best explained by clouds evaporating from the eastern substellar region ($φ\approx$-17 to 48$^\circ$) where temperatures are highest. This is confirmed by comparisons of the phase-resolved spectra with three-dimensional circulation models, which show that NGTS-10 Ab's atmosphere hosts inhomogeneous cloud coverage, likely made-up of $μ$m-sized silicate particles, and weak atmospheric drag ($τ_\mathrm{drag}\gt 10^6$ s). Finally, by measuring the spectral variation of the thermal phase curve offsets, we infer a slope of 7.1$\pm$1.9 degrees per pressure dex, indicative of heat transport that becomes more efficient at depth. Future optical and infrared hot-Jupiter phase curve measurements over a wide range of equilibrium temperatures will enable a complete mapping of the interplay between heat transport and cloud formation in highly-irradiated exoplanet atmospheres.
CommentsAccepted for publication in PASP. 37 pages, 19 figures, 2 tables. arXiv abstract shortened to fit the character limit
