Recipe for Tropical Single Biome Planets

1. Have a planet with a dam' good magnetic field and a thick atmosphere, around 20atm may be enough
2. place it in orbit around a hot star, emitting in UV to soft-Xray at the peak of the black-body radiation spectrum - maybe a young white dwarf? You can put the planet way further than in the case of UV-Vis planets
3. watch how the top of the atmosphere gets fully ionized (and kept in place by the magnetic field), ions persisting for longer (so the night is mostly an aurora, no visible star). This "fluorescence bulb" type of receiving the energy, by shifting the wave length of the incoming radiation to something that pumps up a "normal energy" chemistry, will result in distributing the energy more uniformly around the globe.

The last point is to say "no more cosine law for the insolation dwpendence with latitude, the polar regions included", which allows you to make a uniform climate.

Recipe for Tropical Single Biome Planets

1. Have a planet with a dam' good magnetic field and a thick atmosphere, around 20atm may be enough
2. place it in orbit around a hot star, emitting in UV to soft-Xray at the peak of the black-body radiation spectrum - maybe a young white dwarf? You can put the planet way further than in the case of UV-Vis stars
3. watch how the top of the atmosphere gets fully ionized (and kept in place by the magnetic field), ions persisting for longer (so the night is mostly an aurora, no visible star). This "fluorescence bulb" type of receiving the energy, by shifting the wave length of the incoming radiation to something that pumps up a "normal energy" chemistry, will result in distributing the energy more uniformly around the globe.

The last point is to say "no more cosine law for the insolation dependence with latitude, the polar regions included", which allows you to make a uniform climate.