Dynamics and Temperature Structure of Hot Jupiter Atmospheres

自从十年前首次发现围绕类太阳恒星运行的行星以来（Mayor and Queloz 1995; Marcy and Butler 1996），太阳系外行星的研究迅速取得了一系列惊人的突破。早期的观测立即揭示了太阳系外行星轨道特性的巨大惊喜，迫使我们质疑长期以来关于行星形成和演化的想法：其中大量是“热木星”，之所以这么说，是因为它们质量巨大，轨道离母恒星非常近。不久之后，直接测量了热木星HD209458b的大小（Charbonneau et al. 2000; Henry et al. 2000）和探测到实际的大气层（Charbonneau et al. 2002）和可能沸腾的外逸层（Vidal-Madjar et al. 2003），为研究太阳系外行星的物理性质奠定了基础——超越它们的轨道性质。在过去的一年里，两颗热木星HD209458b和TrES-1发出的热量被斯皮策太空望远镜直接探测到（Deming et al. 2005; Charbonneau et al. 2005）。热发射测量为了解太阳系外行星的物理特性提供了前所未有的机会。这些测量可以对行星上不同阶段的大气进行采样。然而，它们需要复杂的多维流模型来正确解释。这是因为大气运动控制着辐射的空间、时间和光谱行为。在这项工作中，建议对热木星大气的流体动力学过程和热结构进行详细的理论研究，这对指导观测至关重要。该研究将利用先进的数值和解析计算，结合辐射传输计算，更好地约束风的强度，模拟一般环流模式，并确定热木星大气在不同轨道构型（半长轴、偏心、倾角等）下的温度分布。计算得到的流场和温度场将用于太阳系外巨行星的光谱和相位（日食）模型。这项工作也有望推动对一般巨行星的一般环流（如带状和斑点）和长期演化（如冷却和潮汐锁定）的研究。

Since the first discoveries of planets orbiting nearby Sun-like stars, only a decade ago (Mayor and Queloz 1995; Marcy and Butler 1996), there has been a rapid succession of spectacular breakthroughs in extrasolar planet research. Early observations immediately revealed big surprises about the orbital properties of extrasolar planets, forcing us to question long-held ideas about how planets form and evolve: a large number of them were 'Hot Jupiters', so-called because they are massive and orbit very close to their parent stars. Soon after, the direct measurement of the size (Charbonneau et al. 2000; Henry et al 2000) and the detection of an actual atmosphere (Charbonneau et al. 2002) and an exosphere that may be boiling away (Vidal-Madjar et al. 2003) on the Hot Jupiter, HD209458b, laid the groundwork for studying the physical properties of extrasolar planets -- beyond their orbital properties. This past year, heat emitted from two Hot Jupiters, HD209458b and TrES-1, have been directly detected using the Spitzer Space Telescope (Deming et al. 2005; Charbonneau et al. 2005). Heat emission measurements present an unprecedented opportunity to learn about the physical properties of extrasolar planets. The measurements can sample the atmospheres on the planets at different phases. However, they require sophisticated, multi-dimensional flow modelling to interpret properly. This is because atmospheric motions control the spatial, temporal, and spectral behaviour of the emissions. In this effort, it is proposed to carry out a detailed theoretical study of the hydrodynamic processes and thermal structures of Hot Jupiter atmospheres, vital for guiding observations. The study will make use of advanced numerical and analytical calculations that incorporate radiative transfer calculations to better constrain the strength of the winds, model the general circulation pattern, and ascertain the temperature distributions of Hot Jupiter atmospheres in different orbital configurations (semi-major axis, eccentricity, obliquity, etc.). The computed flow and temperature fields will be used by spectral and phase (eclipse) models of extrasolar giant planets. This work is also expected to advance the study of general circulation (e.g., bands and spots) and long-term evolution (e.g., cooling and tidal locking) of giant planets in general.