... Orion Star Colours . ... Red stars are cool, 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. Hydrogen Trifid . ... Clouds of glowing hydrogen gas mingle with dark dust lanes in the Trifid Nebula, a star forming region in the constellation Sagittarius. ... These are galaxies of the Hercules Cluster, an archipelago of "island universes" a mere 650 million light-years distant. ... Vega . ...