We report the detection of an atmosphere on a rocky exoplanet, GJ 1132 b, which is similar to Earth in terms of size and density. The atmospheric transmission spectrum was detected using Hubble WFC3 measurements and shows spectral signatures of aerosol scattering, HCN, and CH₄ in a low mean molecular weight atmosphere. We model the atmospheric loss process and conclude that GJ 1132 b likely lost the original H/He envelope, suggesting that the atmosphere that we detect has been reestablished. We explore the possibility of H₂ mantle degassing, previously identified as a possibility for this planet by theoretical studies, and find that outgassing from ultra-reduced magma could produce the observed atmosphere. In this way we use the observed exoplanet transmission spectrum to gain insights into magma composition for a terrestrial planet. The detection of an atmosphere on this rocky planet raises the possibility that the numerous powerfully irradiated super-Earth planets, believed to be the evaporated cores of sub-Neptunes, may, under favorable circumstances, host detectable atmospheres.

我们报告了在岩石系外行星 GJ 1132 b 上检测到大气层，它的大小和密度与地球相似。大气透射光谱是使用哈勃 WFC3 测量值检测到的，并显示了低平均分子量大气中气溶胶散射、HCN 和 CH _{4 的}光谱特征。我们对大气损失过程进行建模并得出结论，GJ 1132 b 可能丢失了原始的 H/He 包络，这表明我们探测到的大气已经重建。我们探索 H ₂的可能性地幔脱气，先前被理论研究确定为这颗行星的可能性，并发现超还原岩浆的脱气可以产生观察到的大气。通过这种方式，我们使用观测到的系外行星透射光谱来深入了解类地行星的岩浆成分。在这颗岩石行星上探测到大气层，增加了被认为是亚海王星蒸发核心的众多受到强烈辐射的超级地球行星的可能性，在有利的情况下，可能存在可探测的大气层。