论文标题
对于偏心返回黄蜂117b的高质量金属性和甲烷的指示
Indications for very high metallicity and absence of methane for the eccentric exo-Saturn WASP-117b
论文作者
论文摘要
我们研究了长时间的大气组成（$ p _ {\ rm orb} = $ 10天），偏心的Exo-saturn Wasp-117b。 WASP-117B可能处于与WASP-107B相似的大气温度和化学状态。在质量和半径中，黄蜂117b与WASP-39B相似，WASP-39B可以对这些行星进行比较研究。 我们分析了用哈勃太空望远镜/WFC3 G141采集的WASP-117B的近红外传输光谱，该光谱使用两个独立的管道减少了。在光学中，用VLT/浓缩咖啡进行了高分辨率测量。我们报告了稳健的（$3σ$）检测水光谱特征。使用等温温度，均匀的云甲板和平衡化学的1D大气模型，贝叶斯对传输谱进行检索的证据表明，偏爱高大气金属性$ {\ rm [fe/h]} = 2.58^{+0.26} _ {+0.26} _ { - 0.37} _ {-0.37} $ {-0.37} $ and Clear Skies。数据也与较低的金属成分$ {\ rm [fe/h]} <1.75 $和$ 10^{ - 2.2} -10^{ - 5.1} $ bar之间的云甲板，但贝叶斯偏好较弱。我们检索了$ <10^{ - 4} $的低ch $ _4 $丰度在$1σ$和$ <2 \ cdot 10^{ - 1} $ 3σ$之内的$ <2 \ 2 \ 2 \ cdot 10^{ - 1} $。我们不能限制理论上施加的700和1000〜K之间的平衡温度。需要进一步的观察来确认用$ k_ {zz} \ geq 10^8 $ 〜cm $^2 $/s确认CH $ _4 $的淬火。我们报告了VLT/浓缩咖啡高分辨率光谱中Na和K的适应症，并与HST数据结合使用了大量的贝叶斯证据。
We investigate the atmospheric composition of the long period ($P_{\rm orb}=$ 10 days), eccentric exo-Saturn WASP-117b. WASP-117b could be in atmospheric temperature and chemistry similar to WASP-107b. In mass and radius WASP-117b is similar to WASP-39b, which allows a comparative study of these planets. We analyze a near-infrared transmission spectrum of WASP-117b taken with Hubble Space Telescope/WFC3 G141, which was reduced with two independent pipelines. High resolution measurements were taken with VLT/ESPRESSO in the optical. We report the robust ($3σ$) detection of a water spectral feature. Using a 1D atmosphere model with isothermal temperature, uniform cloud deck and equilibrium chemistry, the Bayesian evidence of a retrieval analysis of the transmission spectrum indicates a preference for a high atmospheric metallicity ${\rm [Fe/H]}=2.58^{+0.26}_{-0.37}$ and clear skies. The data are also consistent with a lower-metallicity composition ${\rm [Fe/H]}<1.75$ and a cloud deck between $10^{-2.2} - 10^{-5.1}$ bar, but with weaker Bayesian preference. We retrieve a low CH$_4$ abundance of $<10^{-4}$ volume fraction within $1 σ$ and $<2\cdot 10^{-1}$ volume fraction within $3 σ$. We cannot constrain the equilibrium temperature between theoretically imposed limits of 700 and 1000~K. Further observations are needed to confirm quenching of CH$_4$ with $K_{zz}\geq 10^8$~cm$^2$/s. We report indications of Na and K in the VLT/ESPRESSO high resolution spectrum with substantial Bayesian evidence in combination with HST data.
