Exoplanets & habitability · T_eq = T★ (1 − A)^(1/4) √(R★ / 2a)
Planet Equilibrium Temperature
The temperature a planet settles at from the balance of starlight absorbed and heat radiated, before any greenhouse warming. Earth's is about 255 K (−18 °C); its atmosphere lifts the surface to habitable warmth.
Equilibrium temperature254.59K
Formula: T_eq = T★ (1 − A)^(1/4) √(R★ / 2a)
Worked example
With the default inputs, planet equilibrium temperature evaluates to 254.59 K — Earth (A = 0.3) → ~255 K. The validator recomputes this against the known value on every build, so the formula is checked, not asserted.
Highlights
- ›Earth: ~255 K (before greenhouse)
The physics behind it
Knowledge connections
- Associated withTransit Method
- Associated withEquilibrium Temperature
Sources
The primary and reference sources this topic draws on.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.