Fig. 2: Astrophysical habitability index. | Nature Geoscience
ESI and PHI of all Solar System bodies and each PU \(p_{\mathrm{CO}_2}\) and solar luminosity (Modern (Sol) and solar luminosity in 250 Myr (Sol + 2.5%)) sensitivity study (orange symbols). Values within the green zone indicate habitability (see Methods for details). Values in the red zone indicate poor habitability due to having a rocky interior (high PHI) but not a temperate surface (low ESI) and vice versa. See ref. 20 for ESI and PHI for definitions and planetary body values for the Solar System.