论文标题

了解超热木星HAT-P-7B II的大气特性和化学成分。映射气体动力学的影响

Understanding the atmospheric properties and chemical composition of the ultra-hot Jupiter HAT-P-7b II. Mapping the effects of gas kinetics

论文作者

Molaverdikhani, Karan, Helling, Christiane, Lew, Ben W. P., MacDonald, Ryan J., Samra, Dominic, Iro, Nicolas, Woitke, Peter, Parmentier, Vivien

论文摘要

超热木星的大气通常被认为是在热化学平衡处。我们旨在提供不平衡的化学图,以全球对HAT-P-7B大气中的化学理解,并评估不平衡化学对UHJS的重要性。 我们采用了来自HAT-P-7B 3D GCM的97 1D大气轮廓的层次建模方法。对于每个1D轮廓,我们在化学平衡中与局部气相组成一致评估我们的动力学云形成模型。然后,我们与动力相机方法相比,评估了零阶近似的淬火结果。 我们发现,估计淬火点的零级方法与完整的气体运动建模结果非常吻合。化学不平衡对夜间和早晨丰富的物种具有最大的影响,例如h,h $ _2 $ o,ch $ _4 $,co $ _2 $,hcn和所有c $ _n $ _n $ h $ _m _m $ $ $ $ $ $ $ $ $ $ $ $ $;较重的c $ _n $ h $ _m $ $分子更受不平衡过程的影响。但是,丰度仅受到略微影响。虽然几天的丰度也显着变化,但HAT-P-7B晚上终结者周围的人受到不平衡过程的影响最小。后一个发现可能部分解释了观察到的UHJ的透射光谱与热化学平衡中的大气的一致性。光化学仅会微不足道地影响分子丰度和淬火水平。 通常,与凉爽的热jupiter相比,HAT-P-7B大气的淬火点处于低得多的压力。我们提出了几种途径,以寻找不平衡过程对基于不同当地时期丰度和不透明度测量的UHJ的影响。完全将其与云的化学效应和原始非极性丰度的化学作用完全消除仍然是一个挑战。

The atmospheres of ultra-hot Jupiters are commonly considered to be at thermochemical equilibrium. We aim to provide disequilibrium chemistry maps for a global understanding of the chemistry in HAT-P-7b's atmosphere and assess the importance of disequilibrium chemistry on UHJs. We apply a hierarchical modelling approach utilising 97 1D atmospheric profiles from 3D GCM of HAT-P-7b. For each 1D profile, we evaluate our kinetic cloud formation model consistently with the local gas-phase composition in chemical equilibrium. We then evaluate quenching results from a zeroth-order approximation in comparison to a kinetic gas-phase approach. We find that the zeroth-order approach of estimating quenching points agrees well with the full gas-kinetic modeling results. Chemical disequilibrium has the greatest effect on the nightside and morning abundance of species such as H, H$_2$O, CH$_4$, CO$_2$, HCN, and all C$_n$H$_m$ molecules; heavier C$_n$H$_m$ molecules are more affected by disequilibrium processes. CO abundance, however, is affected only marginally. While dayside abundances also notably change, those around the evening terminator of HAT-P-7b are the least affected by disequilibrium processes. The latter finding may partially explain the consistency of observed transmission spectra of UHJs with atmospheres in thermochemical equilibrium. Photochemistry only negligibly affects molecular abundances and quenching levels. In general, the quenching points of HAT-P-7b's atmosphere are at much lower pressures in comparison to the cooler hot-jupiters. We propose several avenues to look for the effect of disequilibrium processes on UHJs that are, in general, based on abundance and opacity measurements at different local times. It remains a challenge to completely disentangle this from the chemical effects of clouds and that of a primordial non-solar abundance.

扫码加入交流群

加入微信交流群

微信交流群二维码

扫码加入学术交流群,获取更多资源