发表机构
California Institute of Technology; Rutgers, The State University of New Jersey; The Pennsylvania State University; Jet Propulsion Laboratory, California Institute of Technology; University of Colorado Boulder; NASA Goddard Space Flight Center（加州理工学院; 新泽西州立罗格斯大学; 宾夕法尼亚州立大学; 加州理工学院喷气推进实验室; 科罗拉多大学博尔德分校; 美国国家航空航天局戈达德太空飞行中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用 JWST 中红外光谱改进 LHS 3844 b 表面约束，获得最高信噪比发射光谱，识别出 10-12 微米暂定特征，可能对应铁橄榄石表面，并讨论仪器斜坡影响及缓解策略。
AI 中文摘要
系外岩石行星的热发射光谱为了解其表面组成及相应的地质过程提供了窗口。围绕 M 矮星运行的近距离岩石行星是这些研究的理想目标，因为观测表明其中大多数几乎没有大气层。LHS 3844 b 是一颗围绕附近 M 矮星运行的超短周期超级地球，并且是没有白天岩浆海洋的最有利目标。我们展示了这颗行星的更新版 JWST MIRI/LRS 发射光谱（5-12 微米），该光谱来自八次新的和三次存档的掩星观测。我们合并这些观测数据，获得了迄今任何岩石系外行星中最高信噪比的发射光谱，在 12 个波长区间内中位信噪比为 29。我们的数据对多种常见材料的预测 Si-O 伸缩特征（最强的中红外硅酸盐特征）以及透明度特征敏感，后者对成分相对不敏感，并约束表面物质的晶粒尺寸和孔隙度。我们发现 LHS 3844 b 的发射光谱在 10 微米短波方向类似于黑体，不利于透明度特征的存在，并识别出一个 10-12 微米之间的暂定特征（1.9-3.5σ）。如果该特征是天体物理性质的而非仪器性质的，它可以由铁橄榄石（橄榄石的铁端元）表面匹配，但也可能与其他候选行星形成物质如尖晶石或碳化硅一致。我们讨论了波长依赖性仪器斜坡可能引入的偏差，并概述了在未来 LHS 3844 b 观测中减轻这种影响的几种策略，这些观测将确定这颗岩石系外行星的表面组成。
英文摘要
The thermal emission spectra of terrestrial exoplanets provide a window into their surface compositions and corresponding geological processes. Close-in, rocky planets orbiting M dwarfs are ideal targets for these studies, as observations have shown that most have little to no atmosphere. LHS 3844 b is an ultra-short period super-Earth orbiting a nearby M dwarf, and is the most favorable target that does not have a dayside magma ocean. We present an updated JWST MIRI/LRS emission spectrum ($5-12$ $μ$m) of this planet, derived from eight new and three archival eclipse observations. We combine these visits to obtain the highest SNR emission spectrum for any rocky exoplanet thus far, with a median SNR of 29 across 12 wavelength bins. Our data are sensitive to the predicted Si-O stretching feature (the strongest mid-infrared silicate feature) for a wide range of common materials and the transparency feature, which is relatively insensitive to composition and constrains the grain size and porosity of surface materials. We find that LHS 3844 b's emission spectrum resembles a blackbody shortward of 10 $μ$m disfavoring the presence of a transparency feature, and identify a tentative feature ($1.9-3.5σ$) between $10-12$ $μ$m. If this feature is astrophysical and not instrumental in nature, it can be matched by a fayalite (the iron end-member of olivine) surface, but might also be consistent with other candidate planet-forming materials like spinel or silicon carbide. We discuss possible biases introduced by the wavelength-dependent instrumental ramp, and outline several strategies to mitigate this effect in future observations of LHS 3844~b that would establish the surface composition of this rocky exoplanet.
CommentsAccepted for publication in ApJL on October 1, 2026
