论文标题
$ _4 $ $ $ $
The CH$_4$ abundance in Jupiter's upper atmosphere
论文作者
论文摘要
碳氢化合物物种，尤其是CH $ _4 $，在平流层 - 木球的边界中起关键作用，该边界发生在$μ$ bar的压力水平左右。先前对太阳掩星的分析，他和ly-$α$ airglow，以及在3.3 $ $ m左右的ISO/SWS测量结果明显不同。在这里，我们的目标是通过使用综合的非本地非本地热力学平衡模型和在实验室中测量的CH $ _4 $测量的最新碰撞率来准确地对ISO/SWS测量的3.3 $ $ $ $ $ $ radiance进行准确建模。这些发射带已被证明在$ $ $ bar水平上精确地提出了峰值贡献，因此直接探测了感兴趣的区域。我们发现，与最新的分析相比，必须使用高的CH $ _4 $浓度来解释数据，并且该观察结果有利于最新的实验室测量值的下限CH $ _4 $碰撞放松率。我们的结果提供了对木星较低气氛的组成和动力学的精确约束。
Hydrocarbon species, and in particular CH$_4$, play a key role in the stratosphere--thermosphere boundary of Jupiter, which occurs around the $μ$-bar pressure level. Previous analyses of solar occultation, He and Ly-$α$ airglow, and ISO/SWS measurements of the radiance around 3.3 $μ$m have inferred significantly different methane concentrations. Here we aim to accurately model the CH$_4$ radiance at 3.3 $μ$m measured by ISO/SWS by using a comprehensive non-local thermodynamic equilibrium model and the most recent collisional rates measured in the laboratory for CH$_4$ to shed new light onto the methane concentration in the upper atmosphere of Jupiter. These emission bands have been shown to present a peak contribution precisely at the $μ$-bar level, hence directly probing the region of interest. We find that a high CH$_4$ concentration is necessary to explain the data, in contrast with the most recent analyses, and that the observations favour the lower limit of the latest laboratory measurements of the CH$_4$ collisional relaxation rates. Our results provide precise constraints on the composition and dynamics of the lower atmosphere of Jupiter.
