Cold super-Earths that retain their primordial, H–He-dominated atmosphere could have surfaces that are warm enough to host liquid water. This would be due to the collision-induced absorption of infrared light by hydrogen, which increases with pressure. However, the long-term potential for habitability of such planets has not been explored yet. Here we investigate the duration of this potential exotic habitability by simulating planets of different core masses, envelope masses and semi-major axes. We find that terrestrial and super-Earth planets with masses of ~1–10 M_⊕ can maintain temperate surface conditions up to 5–8 Gyr at radial distances larger than ~2 au. The required envelope masses are ~10⁻⁴ M_⊕ (which is 2 orders of magnitude more massive than Earth’s) but can be an order of magnitude smaller (when close-in) or larger (when far out). This result suggests that the concept of planetary habitability should be revisited and made more inclusive with respect to the classical definition.

保持其原始的、以 H-He 为主的大气的寒冷超级地球的表面可能足够温暖以容纳液态水。这可能是由于氢对红外光的碰撞诱导吸收，氢会随着压力的增加而增加。然而，尚未探索此类行星的长期宜居性潜力。在这里，我们通过模拟不同核心质量、包络质量和半长轴的行星来研究这种潜在的外来宜居性的持续时间。我们发现，质量约为 1-10  M _⊕的类地行星和超级地球行星可以在大于 ~2  au的径向距离处保持高达 5-8 Gyr 的温带表面条件。所需的包络质量约为 10 ^-4  M _⊕（比地球的质量大 2 个数量级），但可以小一个数量级（近时）或大（远时）。这一结果表明，应该重新审视行星宜居性的概念，并使其在经典定义方面更具包容性。