Hubble Space Telescope images the Ring Nebula M57

Ring Nebula M57, photographed with the HST WFPC2

The NASA Hubble Space Telescope has captured the sharpest view yet of

the most famous of all planetary nebulae: the Ring Nebula (M57). In this

October 1998 image, the telescope has looked down a barrel of gas cast

off by a dying star thousands of years ago. This photo reveals elongated

dark clumps of material embedded in the gas at the edge of the nebula;

the dying central star floating in a blue haze of hot gas.

The colors are approximately true colors. The color image was assembled

from three black-and-white photos taken through different color filters

with the Hubble telescope’s Wide Field Planetary Camera 2. Blue isolates

emission from very hot helium, which is located primarily close to the

hot central star. Green represents ionized oxygen, which is located

farther from the star. Red shows ionized nitrogen, which is radiated

from the coolest gas, located farthest from the star. The gradations of

color illustrate how the gas glows because it is bathed in ultraviolet

radiation from the remnant central star, whose surface temperature is a

white-hot 216,000 degrees Fahrenheit (120,000 degrees Celsius).

Credit: Hubble Heritage Team (AURA/STScI/NASA)