 Radiative equilibrium

A body is in radiative equilibrium when absorbed radiative power equals emitted radiative power. A surface absorbing flux $F$ and emitting as a grey body has equilibrium temperature $T=(F/(ϵ\sigma ){)}^{1/4}$.

Radiative equilibrium refers to a state in which the energy absorbed by an object or system from incoming radiation is equal to the energy it emits as radiation. In this state, there is no net gain or loss of energy, and the temperature of the object or system remains constant over time. In the context of planetary atmospheres, radiative equilibrium is particularly important for understanding the balance between incoming solar radiation (energy received from the Sun) and outgoing thermal radiation (energy emitted back into space).