North America nebula and Pelican nebula, optical image. The North America nebula (left) is named so due to its similar shape to the continent. The hydrogen gas within this emission nebula is ionised by radiation from nearby hot young stars, making it glow red. The 'east coast', particularly the 'Gulf of Mexico', is defined by a dense cloud of dust (the dark nebula LDN 935) that blocks out light from anything behind it. The Pelican nebula (IC 5070, centre right) is an emission nebula containing the two bright stars 57 Cygni (upper) and 56 Cygni (lower). The bright star on the top right edge is Deneb. Deneb (Alpha Cygni) is the brightest star in Cygnus, the constellation where these nebulae are located.