Austrian Academy of Sciences, Space Research Institute, Graz, Austria.
Institute of Physics, University of Graz, Graz, Austria.
Astrobiology. 2024 Oct;24(10):897-915. doi: 10.1089/ast.2023.0075.
In this hypothesis article, we discuss the basic requirements of planetary environments where aerobe organisms can grow and survive, including atmospheric limitations of millimeter-to-meter-sized biological animal life based on physical limits and O, N, and CO toxicity levels. By assuming that animal-like extraterrestrial organisms adhere to similar limits, we define Earth-like habitats (EH) as rocky exoplanets in the habitable zone for complex life that host N-O-dominated atmospheres with minor amounts of CO, at which advanced animal-like life or potentially even extraterrestrial intelligent life can in principle evolve and exist. We then derive a new formula that can be used to estimate the maximum occurrence rate of such Earth-like habitats in the Galaxy. This contains realistic probabilistic arguments that can be fine-tuned and constrained by atmospheric characterization with future space and ground-based telescopes. As an example, we briefly discuss two specific requirements feeding into our new formula that, although not quantifiable at present, will become scientifically quantifiable in the upcoming decades due to future observations of exoplanets and their atmospheres. Key Words: Eta-Earth-Earth-like habitats-oxygenation time-nitrogen atmospheres-carbon dioxide-animal-like life. Astrobiology 24, 897-915.
在这篇假说文章中，我们讨论了有氧生物能够生长和存活的行星环境的基本要求，包括基于物理限制和 O、N 和 CO 毒性水平的毫米到米大小的生物动物生命的大气限制。通过假设类似动物的外星生物遵循类似的限制，我们将类似地球的栖息地 (EH) 定义为宜居带中的岩石系外行星，这些行星具有 N-O 占主导地位、少量 CO 的大气，在这种环境中，高级类似动物的生命或潜在的外星智能生命可以原则上进化和存在。然后，我们推导出一个新的公式，可以用来估计银河系中类似地球的栖息地的最大出现率。这包含了现实的概率论点，可以通过未来的太空和地面望远镜的大气特征来微调和约束。作为一个例子，我们简要讨论了两个具体的要求，这些要求虽然目前无法量化，但由于未来对系外行星及其大气的观测，将在未来几十年内成为科学上可量化的要求。关键词：Eta-Earth-类似地球的栖息地-富氧时间-氮大气-类似动物的生命。天体生物学 24，897-915。
