| 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 nebula is about a light-year
in diameter and is located some 2,000 light-years from Earth in the direction
of the constellation Lyra. |
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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). |
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