AI 中文总结
结合JWST、HST及地基观测的大气反演显示，GJ 1132 b的透射光谱无特征，当前数据未明确支持其存在大气，更符合裸岩行星模型。
AI 中文摘要
我们结合已发表的Magellan/LDSS3C、HST/WFC3 G141及JWST/NIRSpec（G395H和G395M）的凌星观测数据，获得了GJ 1132 b覆盖0.71至5.16μm的全色透射光谱。使用petitRADTRANS和PyMultiNest，我们开展了贝叶斯大气反演，对比了平线、高斯特征模型以及晴朗和多云大气场景，还测试了是否纳入之前研究中标记为潜在异常值的首次JWST观测数据。纳入短波长光谱后，边际分子偏好从仅JWST数据的H₂O转变为全色数据的NH₃。在测试的7种分子（NH₃、CO₂、CO、CH₄、H₂O、HCN和N₂O）中，仅NH₃显示出边际偏好，排除首次JWST观测后该偏好会减弱。多云大气的贝叶斯证据高于平均分子质量较高的晴朗模型，但均未提供优于平线模型的令人信服的证据。当纳入首次JWST观测时，参考压力P_ref约为10⁻³ bar、以N₂为主（μ约16 amu）且含微量NH₃、H₂O和CH₄的稀薄大气，结合350 nm处不透明度≤10⁻³ cm²·g⁻¹的灰色光学薄幂律云，与平线模型无法区分；排除首次JWST观测后，该模型的可信度进一步降低，支持裸岩解释。我们得出结论，当前光谱未显示GJ 1132 b存在大气的证据，观测结果最符合半径R_p为1.129±0.002 R⊕的裸岩行星；但纳入首次JWST观测时，仍无法排除存在稀薄、被遮蔽大气的可能。
英文摘要
We present a panchromatic transmission spectrum of GJ1132b spanning $0.71$--$5.16~μ$m, combining published transit observations from Magellan/LDSS3C, HST/WFC3 G141, and JWST/NIRSpec (G395H and G395M). Using petitRADTRANS and PyMultiNest, we perform Bayesian atmospheric retrievals, comparing a flat-line, Gaussian-feature models, and clear and cloudy atmospheric scenarios, including tests with and without the first JWST visit flagged as a potential outlier in a previous study. The inclusion of shorter-wavelength spectra shifts the marginal molecular preference from H$_2$O (JWST-only) to NH$_3$ (panchromatic). Of the seven molecules tested (NH$_3$, CO$_2$, CO, CH$_4$, H$_2$O, HCN, and N$_2$O), only NH$_3$ shows a marginal preference, which is weakened when the JWST first visit is excluded. Cloudy atmospheres yield higher Bayesian evidence than high-mean-molecular-weight clear models, but none provides compelling evidence over the flat-line scenario. A thin ($P_{\rm ref} \sim 10^{-3}$~bar), N$_2$-dominated atmosphere ($μ\sim 16$~amu) with traces of NH$_3$, H$_2$O, and CH$_4$, combined with a grey, optically thin power-law cloud (opacity at 350~nm $\le 10^{-3}~{\rm cm^2\,g^{-1}}$), remains indistinguishable from the flat-line model when the first JWST visit is included and is further disfavoured when it is excluded, strengthening a bare-rock interpretation. We conclude that current spectra show no evidence for an atmosphere on GJ1132b. The observations are best explained by a bare rocky planet with $R_{\rm p} = 1.129 \pm 0.002\,R_\oplus$, though a tenuous, obscured atmosphere cannot be excluded when the JWST first visit is included.
Comments26 pages, accepted for publication in MNRAS
