A planet orbits a red dwarf star of radius r0 at a distance of 120r0. In- telligent beings on this planet observe that the radiation from their star arriving at the top of their atmosphere is 1100W/m2. Assume the star’s radiation follows Planck’s law for black body radiation. a) What is the temperature of the star’s surface, within 10K accuracy? b) What is the color of the star’s light? This would correspond to the frequency at which the function B(ν, T) is maximal.

A planet orbits a red dwarf star of radius r0 at a distance of 120r0. In- telligent beings on this planet observe that the radiation from their star arriving at the top of their atmosphere is 1100W/m2. Assume the star’s radiation follows Planck’s law for black body radiation. a) What is the temperature of the star’s surface, within 10K accuracy? b) What is the color of the star’s light? This would correspond to the frequency at which the function B(ν, T) is maximal.