Object Analysis

The Little Gem Nebula (NGC 6818) is a planetary nebula located in the constellation of Sagittarius. It is located at a distance of about 6,000 light-years. It gets its name from its appearance in small telescopes: a tiny, glittering teal-colored gem.

The nebula has a diameter of just over half a light-year. It consists of a bright, turquoise inner bubble surrounded by a fainter, spherical outer shell. The central star is a magnitude 15 white dwarf that is extremely hot, powering the nebula's fluorescence.

Hubble images reveal a hole in the inner shell, likely punched by a fast stellar wind from the central star. This wind is moving at hundreds of kilometers per second, colliding with the slower moving gas of the outer shell and creating bright X-ray hotspots.