Eta-Earth Revisited I: A Formula for Estimating the Maximum Number of Earth-like Habitats
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 O2, N2, and CO2 toxicity levels.
By assuming that animal-like extraterrestrial organisms adhere to similar limits, we define Earth-like Habitats (ηEH) as rocky exoplanets in the Habitable Zone of Complex Life that host N2-O2-dominated atmospheres with minor amounts of CO2, at which advanced animal-like 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.
Helmut Lammer, Manuel Scherf, Laurenz Sproß
Comments: accepted manuscript submitted to Astrobiology, 62 pages, 6 figures; link to published version: this https URL
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2412.05005 [astro-ph.EP] (or arXiv:2412.05005v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2412.05005
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Journal reference: Astrobiology, 24, 10, 897, 2024
Related DOI:
https://doi.org/10.1089/ast.2023.007
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Submission history
From: Manuel Scherf
[v1] Fri, 6 Dec 2024 12:59:09 UTC (1,369 KB)
https://arxiv.org/abs/2412.05005
Astrobiology,
