solar luminosity Archives

Carbonate-silicate weathering feedback behavior throughout the habitable zone (HZ). (a) Reproduction of O. R. Lehmer et al. (2020) results showing stable, Earth-like climates generated by their habitable zone weathering model. The x-axis shows stellar flux normalized to the solar constant (S/S⊕), the y-axis shows atmospheric CO2 partial pressure (pCO2), and the z-axis shows the distribution of pCO2 values at each S/S⊕. Black squares mark modern Earth and Mars (S, pCO2) values. Point color indicates relative density (yellow = low, purple = high). The model predicts increasing atmospheric CO2 with decreasing stellar flux within the HZ. (b-d) Kernel density estimates (KDE) of pCO2 for simulated planets at 1.0 (b), 0.75 (c), and 0.50 S/S⊕ (d). While panels b-d reflect model parameter variations in pCO2, similar distributions would be expected in observational data if a CO2-buffering feedback is operative, highlighting the ideal dataset for applying our method. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Status Report

Observational Tests of Terrestrial Planet Buffering Feedbacks and the Habitable Zone Concept

by Keith CowingSeptember 7, 2025September 7, 2025

The habitable zone is defined as the orbital region around a star where planetary feedback cycles buffer atmospheric greenhouse gases that, in combination with solar luminosity, maintain surface temperatures suitable […]

CO2 reservoir sizes of the atmosphere (Patm) (a–c), and the fractional habitability (fhab) (d–f) calculated with respect to different obliquity and total exchangeable reservoir size (Ptot) under present solar luminosity (a, d), different solar luminosity and Ptot under an obliquity of 10˚ (b, e), and different obliquity and Ptot under solar luminosity of 0.75 times relative to the present value (c,f). The region “NP only” represents the solution with the permanent ice only at the north pole. The Patm values shown in a, b, and c are the maximum value that is possible in each condition. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Gaia - Planetary Perspectives, Habitable Zones, Mars, Status Report

Behaviors of Martian CO2-driven Dry Climate System and Conditions for Atmospheric Collapses

by Keith CowingNovember 14, 2024November 14, 2024

The present Martian climate is characterized by a cold and dry environment with a thin atmosphere of carbon dioxides (CO2).

solar luminosity

Observational Tests of Terrestrial Planet Buffering Feedbacks and the Habitable Zone Concept

Behaviors of Martian CO2-driven Dry Climate System and Conditions for Atmospheric Collapses

The Emergence Of Life In The Light Of Evolution

ReactionAtlas: Ab Origine Exploration Of Chemical Reaction Networks With Machine Learning

Mass Constraints For The K2-223 System Planets: An Ultra-short-period sub-Earth, A Short-period Super-Earth, And A Tentative Long-period Giant Planet

Double Gravity-Assist Rendezvous Trajectory to Halley’s Comet Using Deep-Space Low Thrust

Photometric Characterization Of Near-Earth Asteroids: Rotation, Taxonomy, And Candidate Evidence For Internal Cohesion