The Veil Nebula is a cloud of heated and ionized gas and dust in the constellation Cygnus. It forms the visible parts of the Cygnus Loop, a supernova remnant, many parts of which have received their own individual names and catalog identifiers. The source supernova was a star 20 times as massive as the sun and exploded 10.000 to 20.000 years ago. The remains have since expanded to cover an area of the sky approximately 3 degrees in diameter.