Abell 39, also known as PN A66 39, is a planetary nebula located in the constellation Hercules. Abell 39 lies at a distance of approximately 6,800 light-years from Earth. It spans a true diameter of roughly 5 light-years and has an apparent diameter of around 2.7 arcminutes on the sky. At its centre sits a hot white dwarf, the remnant of the star that shed its outer layers to create the nebula, estimated to have occurred around 22,000 years ago.