Star Colors in Orion
Credit & Copyright: Jens Hackmann
Explanation: What determines a star’s color? Its temperature. Red stars are cool, with surface temperatures of around 3,000 kelvins (K), while blue stars are hotter and can have temperatures over 30,000 K. Our own lovely “yellow” Sun’s temperature is a comforting 6,000 K. Differences in star colors are particularly easy to see in this intriguing composite view of the constellation Orion, made while experimenting with a star trail step-focus technique.