A Two-Tier Framework for Exoplanet Habitability: Earth Similarity Index and Planetary Habitability Index
To the point
A two-tier framework screens exoplanets by first measuring Earth-like similarity through mass, radius, and temperature, then evaluating overall habitability with a Planetary Habitability Index that requires a stable substrate, available energy, suitable chemistry, and a liquid solvent, designed to minimize Earth-life bias and to improve as new data and missions become available.
