images

M57 (NGC 6720) planetary nebula in Lyra

by

E.Mouquet/Novapix

Reference

a-nep67-20003

Date

2007-01-22

The Ring Nebula, M57, is the most famous example of a planetary nebula. Located about 2,000 light years away, it has an apparent diameter of 1 arc minute and a real diameter of about one light year. At magnitude 9.0 its high surface brightness makes it an easy object, even from the city and even with small telescopes. Planetary nebula are shells of gas shed by stars late in their life cycles after using up all of their nuclear fuel. The star then ejects a significant portion of its mass in a gaseous shell, which is illuminated by its extremely hot central star, which is just the core left from the original star.