IC 4628

South of Antares, in the tail of the nebula-rich constellation Scorpius, lies emission nebula IC 4628, also known as the Prawn Nebula and GUM 56. Nearby hot, massive stars, millions of years young, irradiate the nebula with invisible ultraviolet light, stripping electrons from atoms. The electrons eventually recombine with the atoms to produce the visible nebular glow, dominated by the red emission of hydrogen. At an estimated distance of 6,000 light-years, the region shown is about 250 light-years across, spanning over three full moons on the sky.