There is something about inverse square laws which makes them break down at extremities. Einstein showed this in the past with General Relativity. The inverse square law for calculating irradiance from a star is a direct consequence of conservation of energy. However, there are limitations to the inverse square law when we talk about a planet very close to its host star. 

I was fortunate to get a chance to work on a project that makes a case about how inverse square law breaks down for a particular latitude on the planet and suggests a new mathematical model that can supersede it. The adjacent figure shows that at high latitudes we see a deviation from inverse square law. This deviation when incorporated in the General Circulation Model (GCM) may alter the predictions about the planet's climate.

I developed a novel code for modelling the irradiation on such planets. It can be found here.