Maps of surface temperatures (averaged over 50 Earth days) for TRAPPIST-1f, g and h, assuming initially cold, water ice covered frozen planets, endowed with a pure N₂ atmosphere (with H₂O as a variable gas) at three different surface pressure (10 millibars, 100 millibars, 1 bar). Blue colored label indicates the mininum temperature reached by the coldest point of the planet throughout the entire simulation. As a reminder, for partial pressures of 10 millibars (100 millibars and 1 bar), N₂ is expected to collapse at 53 K (62 K and 79 K), CO at 56 K (66 K and 83 K), and O₂ at 61 K (72 K and 87 K). The geothermal heat flux is not taken into account, but the coldest temperatures found in these cases a posteriori show that it can be neglected.