TOI-2257 b and known exoplanets in the context of their equilibrium temperature (x axis) and TSM (y axis). Different symbols and colors designate different planet size categories. TOI-2257 b lies in the middle of the blue shaded area, which highlights sub-Neptunes (i) that are amenable for atmospheric characterization (TSM > 12) and (ii) for which life in the clouds is possible (T_eq between 200 and 320 K, following Seager et al. 2021). Equilibrium temperatures were estimated using an albedo of 0 and an emissivity of 1, following Kempton et al. (2018). Altering the assumptions for albedo and emissivity (e.g., assuming an albedo of 0.3, as for Earth and Neptune) adds lower error bars of ~10% and upper error bars of ~30% to the shown temperatures. Data were retrieved from the Exoplanet Archive (https://exoplanetarchive.ipac.caltech.edu/) on 2021 July 30. The figure has been adapted from Seager et al. (2021).