Retrieval of exoplanet emission spectra with HyDRA
Retrieval of exoplanet emission spectra with HyDRA
复制标题
使用 HyDRA 检索系外行星发射光谱
DOI：
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
N. Madhusudhan
中科院分区：
文献类型：
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作者：
S. Gandhi;N. Madhusudhan
系外行星的热发射光谱对系外行星大气中的化学成分、压力-温度（P-T）分布和能量传输提供了限制。这些属性的准确推断依赖于所采用的大气反演方法的稳健性。虽然现有的检索代码对几种系外行星大气中的分子丰度和温度剖面提供了显着的限制，但对其热平衡和化学平衡偏差的限制尚未得到充分探索。我们目前的工作是朝这个方向迈出的一步。我们报告了 HyDRA，一种外行星大气热发射光谱的不平衡反演框架。检索代码使用参数大气模型的标准架构以及使用嵌套采样算法的贝叶斯统计推断。对于给定的数据集，检索到的成分和 P-T 剖面与 GENESIS 自洽大气模型一起使用，以限制可观测大气中化学和辐射对流平衡的逐层偏差。我们在 Hot Jupiter WASP-43b 上展示了具有高精度发射光谱的 HyDRA。我们检索到的 H2O 混合比为 log(H2O) = -3.54^{+0.82}_{-0.52}，与之前的研究一致。我们检测到 H2O 和 CO/CO2 的组合，显着性为 8 西格玛。我们发现白天 P-T 剖面与 1-sigma 限制内的辐射对流平衡一致，并且昼夜重新分布较低，这与之前的研究一致。导出的成分也与相应的 P-T 分布分布的热化学平衡一致。在高精度和高分辨率发射光谱时代，HyDRA 为检索系外行星大气中的不平衡现象提供了一条途径。
Thermal emission spectra of exoplanets provide constraints on the chemical compositions, pressure-temperature (P-T) profiles, and energy transport in exoplanetary atmospheres. Accurate inferences of these properties rely on the robustness of the atmospheric retrieval methods employed. While extant retrieval codes have provided significant constraints on molecular abundances and temperature profiles in several exoplanetary atmospheres, the constraints on their deviations from thermal and chemical equilibria have yet to be fully explored. Our present work is a step in this direction. We report HyDRA, a disequilibrium retrieval framework for thermal emission spectra of exoplanetary atmospheres. The retrieval code uses the standard architecture of a parametric atmospheric model coupled with Bayesian statistical inference using the Nested Sampling algorithm. For a given dataset, the retrieved compositions and P-T profiles are used in tandem with the GENESIS self-consistent atmospheric model to constrain layer-by-layer deviations from chemical and radiative-convective equilibrium in the observable atmosphere. We demonstrate HyDRA on the Hot Jupiter WASP-43b with a high-precision emission spectrum. We retrieve an H2O mixing ratio of log(H2O) = -3.54^{+0.82}_{-0.52}, consistent with previous studies. We detect H2O and a combined CO/CO2 at 8-sigma significance. We find the dayside P-T profile to be consistent with radiative-convective equilibrium within the 1-sigma limits and with low day-night redistribution, consistent with previous studies. The derived compositions are also consistent with thermochemical equilibrium for the corresponding distribution of P-T profiles. In the era of high precision and high resolution emission spectroscopy, HyDRA provides a path to retrieve disequilibrium phenomena in exoplanetary atmospheres.
影响因子：
4.8
作者：
R. MacDonald;N. Madhusudhan
通讯作者：
R. MacDonald;N. Madhusudhan
影响因子：
1.4
作者：
J. Tennyson;S. Yurchenko;A. Al-Refaie;Victoria H J Clark;K. Chubb;E. Conway;Akhil Dewan;Maire N Gorman;C. Hill;A. Lynas-Gray;Thomas M. Mellor;Laura K. McKemmish;A. Owens;O. Polyansky;M. Semenov;W. Somogyi;G. Tinetti;Apoorva Upadhyay;I. Waldmann;Yixin Wang;Samuel Wright;O. Yurchenko
通讯作者：
J. Tennyson;S. Yurchenko;A. Al-Refaie;Victoria H J Clark;K. Chubb;E. Conway;Akhil Dewan;Maire N Gorman;C. Hill;A. Lynas-Gray;Thomas M. Mellor;Laura K. McKemmish;A. Owens;O. Polyansky;M. Semenov;W. Somogyi;G. Tinetti;Apoorva Upadhyay;I. Waldmann;Yixin Wang;Samuel Wright;O. Yurchenko