arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节(Veterans Day),12 日无更新
arXiv 1607.03230astro-ph.EP
收藏

非均匀热结构对系外行星发射光谱解释的影响

The Impact of Non-Uniform Thermal Structure on the Interpretation of Exoplanet Emission Spectra

Y. Katherina Feng, Michael R. Line, Jonathan J. Fortney, Kevin B. Stevenson, Jacob Bean, Laura Kreidberg, Vivien Parmentier

摘要:

通过光谱学确定大气结构和行星大气的分子丰度涉及模型和数据之间的直接比较。虽然复杂程度不同,但大多数模型光谱比较基本上都假设“1D”模型物理。然而,来自大气环流模型和太阳系行星的知识表明,行星大气的结构和组成本质上是“三维”的。我们探讨了潜在的偏见导致标准的“一维”的贝叶斯大气反演框架内的假设。具体来说,我们展示了如何假设一个单一的1维热剖面可以偏置我们的热发射光谱的热木星大气层,是由两个热剖面的解释。我们检索后的光谱未解决的模型行星观测与$HST$ WFC 3 + $Spitzer$ IRAC以及$JWST$在不同的差异下,在两个热配置文件。对于WFC 3 +IRAC,当对比度为80%时,使用1D模型对CH $_4$丰度的估计存在显著偏倚。对于$JWST$,当对比度大于40%时,需要两个热剖面来充分解释数据并估计丰度。我们还将这个初步的概念应用到最近的热木星WASP-43 b的WFC 3 +IRAC相位曲线数据。我们在模拟数据中看到了类似的行为:虽然H $_2$ O丰度测定是稳健的,但CH $_4$在1D假设下被人为地良好约束到不正确的值。我们的工作表明,需要评估模型的假设,以提取有意义的限制,从大气光谱和激励探索最佳的观测设置。

英文摘要:

The determination of atmospheric structure and molecular abundances of planetary atmospheres via spectroscopy involves direct comparisons between models and data. While varying in sophistication, most model-spectra comparisons fundamentally assume "1D" model physics. However, knowledge from general circulation models and of solar system planets suggests that planetary atmospheres are inherently "3D" in their structure and composition. We explore the potential biases resulting from standard "1D" assumptions within a Bayesian atmospheric retrieval framework. Specifically, we show how the assumption of a single 1-dimensional thermal profile can bias our interpretation of the thermal emission spectrum of a hot Jupiter atmosphere that is composed of two thermal profiles. We retrieve upon spectra of unresolved model planets as observed with a combination of $HST$ WFC3+$Spitzer$ IRAC as well as $JWST$ under varying differences in the two thermal profiles. For WFC3+IRAC, there is a significantly biased estimate of CH$_4$ abundance using a 1D model when the contrast is 80%. For $JWST$, two thermal profiles are required to adequately interpret the data and estimate the abundances when contrast is greater than 40%. We also apply this preliminary concept to the recent WFC3+IRAC phase curve data of the hot Jupiter WASP-43b. We see similar behavior as present in our simulated data: while the H$_2$O abundance determination is robust, CH$_4$ is artificially well-constrained to incorrect values under the 1D assumption. Our work demonstrates the need to evaluate model assumptions in order to extract meaningful constraints from atmospheric spectra and motivates exploration of optimal observational setups.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑