Temperature and Distance: A Constant?

• If distance from the Sun were the only factor in determining a planet’s temperature, we should be able to develop a constant using those two variables.
• For example: If you multiply the temperature of each planet by the square of the distance from the Sun as below, you should get a number that is very similar for each planet… a CONSTANT.

Source: The Scale of the Heliosphere and Nearby Galactic Neighborhood | NASA