1 Zentrum für Astronomie und Astrophysik, Technische Universität Berlin , Berlin, Germany .
2 Institut für Planetenforschung , Deutsches Zentrum für Luft- und Raumfahrt, Berlin, Germany .
Astrobiology. 2018 Feb;18(2):116-132. doi: 10.1089/ast.2016.1632. Epub 2018 Jan 24.
Understanding the possible climatic conditions on rocky extrasolar planets, and thereby their potential habitability, is one of the major subjects of exoplanet research. Determining how the climate, as well as potential atmospheric biosignatures, changes under different conditions is a key aspect when studying Earth-like exoplanets. One important property is the atmospheric mass, hence pressure and its influence on the climatic conditions. Therefore, the aim of the present study is to understand the influence of atmospheric mass on climate, hence habitability, and the spectral appearance of planets with Earth-like, that is, N-O dominated, atmospheres orbiting the Sun at 1 AU. This work utilizes a 1D coupled, cloud-free, climate-photochemical atmospheric column model; varies atmospheric surface pressure from 0.5 to 30 bar; and investigates temperature and key species profiles, as well as emission and brightness temperature spectra in a range between 2 and 20 μm. Increasing the surface pressure up to 4 bar leads to an increase in the surface temperature due to increased greenhouse warming. Above this point, Rayleigh scattering dominates, and the surface temperature decreases, reaching surface temperatures below 273 K (approximately at ∼34 bar surface pressure). For ozone, nitrous oxide, water, methane, and carbon dioxide, the spectral response either increases with surface temperature or pressure depending on the species. Masking effects occur, for example, for the bands of the biosignatures ozone and nitrous oxide by carbon dioxide, which could be visible in low carbon dioxide atmospheres. Key Words: Planetary habitability and biosignatures-Atmospheres-Radiative transfer. Astrobiology 18, 116-132.
了解岩石系外行星上可能的气候条件，从而了解它们的潜在可居性，是系外行星研究的主要课题之一。在研究类地系外行星时，确定气候以及潜在大气生物特征在不同条件下如何变化是一个关键方面。一个重要的特性是大气质量，因此是压力及其对气候条件的影响。因此，本研究的目的是了解大气质量对气候进而对可居性的影响，以及在距离太阳 1AU 处绕太阳运行的具有类地、即 N-O 为主的大气的行星的光谱外观。这项工作利用了一维耦合、无云、气候光化学反应大气柱模型；大气表面压力从 0.5 到 30 巴不等；并在 2 到 20μm 的范围内研究了温度和关键物种分布，以及发射和亮度温度光谱。将表面压力增加到 4 巴会导致由于温室变暖而导致表面温度升高。在这一点之上，瑞利散射占主导地位，表面温度下降，达到低于 273 K 的表面温度（大约在约 34 巴的表面压力下）。对于臭氧、氧化亚氮、水、甲烷和二氧化碳，光谱响应要么随表面温度增加，要么随压力增加，具体取决于物种。例如，二氧化碳对生物特征臭氧和氧化亚氮的谱带会发生掩蔽效应，在二氧化碳含量低的大气中可能会看到这些谱带。关键词：行星可居性和生物特征-大气-辐射转移。天体生物学 18，116-132。
