近日，美国哈佛大学Collin Cherubim团队报道了氦从附近一颗绕宜居带运行的岩石系外行星的大气层中逸出。相关论文发表在2026年9月3日出版的《科学》杂志上。

对高度辐照的气态巨系外行星的观测表明，氦正从其大气中逃逸。关于岩石系外行星存在大气的证据有限，这可能是因为它们的大气早已逃逸。

研究组报告了LHS 1140b的近红外光谱观测结果，这是一颗位于附近低质量恒星宜居带内的岩石系外行星。凌日光谱显示，该行星大气中存在氦吸收。氦吸收在2024年被探测到，但在2025年未被探测到，表明大气逃逸具有时间变化性。研究组将这些结果解释为：上层大气以氦为主且氢贫乏，其他挥发性物质被束缚在较低高度，这与大气分馏模型一致。在同一系统中，对更小且受到更强辐照的系外行星LHS 1140c，未探测到氦吸收。

附：英文原文

Title: Helium escaping from the atmosphere of a nearby rocky exoplanet orbiting in a habitable zone

Author: Collin Cherubim, Shreyas Vissapragada, Tim Cunningham, Annabella G. Meech, David Charbonneau, Robin Wordsworth, Aaron Householder, Johanna Teske, Leonardo A. Dos Santos, Nicole L. Wallack, William Misener, Zifan Lin, Andrew McWilliam, Michael Zhang, Jason A. Dittmann, Mercedes López-Morales

Issue&Volume: 2026-09-03

Abstract: Observations of highly irradiated gas giant exoplanets have shown helium escaping from their atmospheres. There is limited evidence for atmospheres on rocky exoplanets, perhaps because they have already escaped. We report near-infrared spectroscopic observations of LHS 1140b, a rocky exoplanet that orbits in the habitable zone of a nearby low-mass star. The transit spectra show absorption by helium escaping from the planet’s atmosphere. Helium absorption is detected in 2024 but not in 2025, indicating time-variable atmospheric escape. We interpret these results as indicating an upper atmosphere dominated by helium and depleted in hydrogen, with other volatile species trapped at lower altitudes, which is consistent with atmospheric fractionation models. No helium absorption is detected for LHS 1140c, a smaller and more strongly irradiated exoplanet in the same system.

DOI: 10.1126/science.aea9708

Source: https://www.science.org/doi/10.1126/science.aea9708