Kuzucan Asena, Bolmont Emeline, Chaverot Guillaume, Ferreira Jaqueline Quirino, Ibelings Bastiaan Willem, Bhatnagar Siddharth, McGinnis Daniel Frank
Observatoire de Genève, Université de Genève, Chemin Pegasi 51, 1290 Versoix, Switzerland.
Centre sur la Vie dans l'Univers, Université de Genève, 1211 Geneva, Switzerland.
Life (Basel). 2025 Jan 10;15(1):79. doi: 10.3390/life15010079.
Studying exoplanet atmospheres is essential for assessing their potential to host liquid water and their capacity to support life (their habitability). Each atmosphere uniquely influences the likelihood of surface liquid water, defining the habitable zone (HZ)-the region around a star where liquid water can exist. However, being within the HZ does not guarantee habitability, as life requires more than just liquid water. In this study, we adopted a two-pronged approach. First, we estimated the surface conditions of planets near the HZ's inner edge under various atmospheric compositions. By utilizing a 3D climate model, we refined the inner boundaries of the HZ for planets with atmospheres dominated by H and CO for the first time. Second, we investigated microbial survival in these environments, conducting laboratory experiments on the growth and survival of K-12, focusing on the impact of different gas compositions. This innovative combination of climate modeling and biological experiments bridges theoretical climate predictions with biological outcomes. Our findings indicate that atmospheric composition significantly affects bacterial growth patterns, highlighting the importance of considering diverse atmospheres in evaluating exoplanet habitability and advancing the search for life beyond Earth.
研究系外行星的大气层对于评估它们容纳液态水的潜力以及支持生命的能力（即宜居性）至关重要。每颗行星的大气层都独特地影响着表面液态水存在的可能性，从而确定了宜居带（HZ）——恒星周围液态水能够存在的区域。然而，处于宜居带内并不保证具有宜居性，因为生命所需的不仅仅是液态水。在这项研究中，我们采用了双管齐下的方法。首先，我们估计了处于宜居带内边缘附近的行星在各种大气组成下的表面状况。通过使用三维气候模型，我们首次细化了以氢和一氧化碳为主导大气的行星的宜居带内边界。其次，我们研究了微生物在这些环境中的生存情况，对K-12的生长和存活进行了实验室实验，重点关注不同气体组成的影响。气候建模与生物学实验的这种创新结合，将理论气候预测与生物学结果联系起来。我们的研究结果表明，大气组成显著影响细菌的生长模式，凸显了在评估系外行星宜居性和推进地外生命搜索过程中考虑多种大气层的重要性。
