Cone nebula, optical image. The Cone is the dark triangular intrusion at lower centre. It forms part of emission nebula NGC 2264 and holds embryonic stars, which are formed from coalescing dust and gas clouds and can be seen as minute white specks in the tip of the cone. NGC 2264 is powered by a hot young cluster of stars, the brightest of which is S or 15 Monocerotis (upper centre). Ultraviolet radiation from these stars ionises the hydrogen gas in the nebula, causing it to glow. NGC 2264 is found about 2600 light years from Earth, in the constellation Monoceros. This image was produced using the Canada-France-Hawaii Telescope, Mauna Kea, Hawaii, USA.