An important focus of exoplanet research is the determination of the atmospheric temperature structure of strongly irradiated gas giant planets, or hot Jupiters. HD 209458b is the prototypical exoplanet for atmospheric thermal inversions, but this assertion does not take into account recently obtained data or newer data reduction techniques. We reexamine this claim by investigating all publicly available Spitzer Space Telescope secondary-eclipse photometric data of HD 209458b and performing a self-consistent analysis. We employ data reduction techniques that minimize stellar centroid variations, apply sophisticated models to known Spitzer systematics, and account for time-correlated noise in the data. We derive new secondary-eclipse depths of 0.119% ± 0.007%, 0.123% ± 0.006%, 0.134% ± 0.035%, and 0.215% ± 0.008% in the 3.6, 4.5, 5.8, and 8.0 μm bandpasses, respectively. We feed these results into a Bayesian atmospheric retrieval analysis and determine that it is unnecessary to invoke a thermal inversion to explain our secondary-eclipse depths. The data are well fitted by a temperature model that decreases monotonically between pressure levels of 1 and 0.01 bars. We conclude that there is no evidence for a thermal inversion in the atmosphere of HD 209458b.
展开▼
机译：系外行星研究的重要重点是确定强辐射气体巨型行星或热木星的大气温度结构。 HD 209458b是大气热反转的典型系外行星，但该主张未考虑到最近获得的数据或较新的数据约简技术。我们将通过调查HD 209458b的所有公开可用的Spitzer空间望远镜的次蚀光度数据并进行自洽分析来重新检查该声明。我们采用数据缩减技术来最大程度地减少恒星质心变化，将复杂的模型应用于已知的Spitzer系统，并考虑数据中与时间相关的噪声。在3.6、4.5、5.8和8.0μm带通中，我们得出的新的日食深度分别为0.119％±0.007％，0.123％±0.006％，0.134％±0.035％和0.215％±0.008％。我们将这些结果输入贝叶斯大气反演分析中，并确定没有必要调用热反演来解释我们的次食深度。温度模型很好地拟合了数据，该模型在1 bar和0.01 bar的压力水平之间单调降低。我们得出的结论是，没有证据表明HD 209458b的大气发生热转化。
展开▼
