The Flaming Star Nebula (IC 405, SH 2-229, or Caldwell 31) is an emission/reflection nebula about 1,500 light-years away in the constellation Auriga. The nebula is about 5 light-years across and surrounds the young irregular variable star AE Aurigae, a runaway star that is believed to have been ejected from the Orion Nebula some 2.7 million years ago.
This diffuse nebula that mainly surrounds the star AE Aurigae, visible just below the center of the image, gives the impression that the star is burning, hence its name.
The material that appears as smoke is mostly interstellar hydrogen, but does contain smoke-like dark filaments of carbon-rich dust grains. The red and purple colors of the nebula are present in different regions and are created by different processes.
The bright star AE Aurigae is so hot it is blue, emitting light so energetic it knocks electrons away from surrounding gas. When a proton recaptures an electron, red light is frequently emitted, as seen in the surrounding emission nebula.
The purple region’s color is a mix of this red light and blue light emitted by AE Aurigae but reflected to us by surrounding dust. The two regions of IC 405 are referred to as a red emission nebula and a blue reflection nebula.