- The Stingray Nebula (Hen 3-1357) is the youngest-known planetary nebula, having appeared in the 1980s. The nebula is located in the direction of the southern constellation Ara (the Altar), and is located 18,000 light-years (5,600 parsecs) away. Although it is some 130 times the size of the Solar System, the Stingray Nebula is only about one tenth the size of most other known planetary nebulae. The central star of the nebula is the fast-evolving star SAO 244567. Until the early 1970s, it was observed on Earth as a preplanetary nebula in which the gas had not yet become hot and ionized.