Why are red stars red, despite being hotter than a blue flame?

Question

At 1500 C, iron glows “[dazzling white](https://en.wikipedia.org/wiki/Red_heat)”.
At roughly 2000 C, [propane](https://en.wikipedia.org/wiki/Gas_burner) burns [blue](https://en.wikipedia.org/wiki/Gas_burner#/media/File:Propane-burner.jpg).
At 3551 C, [Mu Cephei](https://en.wikipedia.org/wiki/Mu_Cephei) earned the name “Herschel’s Garnet Star”, and this is not a reference to uvarovite.

Why?

In: 37

Answer 1

Mu Cephei is a red supergiant star, the reddest star visible to the naked eye. It has an estimated surface temperature of 3,551 K (3,278 °C; 5,932 °F). This temperature is hot enough to cause the star to emit a reddish-orange light, which is why it has earned the nickname Herschel’s Garnet Star. The color is caused by the absorption of blue and green light by the star’s atmosphere, which is composed mostly of hydrogen and helium.