| In
its first glimpse of the heavens following the successful December 1999
servicing mission, NASA's Hubble Space Telescope has captured a majestic
view of a planetary nebula, the glowing remains of a dying, Sun-like star.
This stellar relic, first spied by William Herschel in 1787, is nicknamed
the "Eskimo" Nebula (NGC 2392) because, when viewed through ground-based
telescopes, it resembles a face surrounded by a fur parka. In this Hubble
telescope image, the "parka" is really a disk of material embellished with
a ring of comet-shaped objects, with their tails streaming away from the
central, dying star. The Eskimo's "face" also contains some fascinating
details. Although this bright central region resembles a ball of twine,
it is, in reality, a bubble of material being blown into space by the central
star's intense "wind" of high-speed material.
The planetary nebula began forming about 10,000 years ago, when the
dying star began flinging material into space. The nebula is composed
of two elliptically shaped lobes of matter streaming above and below the
dying star. In this photo, one bubble lies in front of the other, obscuring
part of the second lobe.
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Scientists
believe that a ring of dense material around the star's equator, ejected
during its red giant phase, created the nebula's shape. This dense waist
of material is plodding along at 72,000 miles per hour (115,000 kilometers
per hour), preventing high-velocity stellar winds from pushing matter along
the equator. Instead, the 900,000-mile-per-hour (1.5-million-kilometer-per-hour)
winds are sweeping the material above and below the star, creating the elongated
bubbles. The bubbles are not smooth like balloons but have filaments of
denser matter. Each bubble is about 1 light-year long and about half a light-year
wide. Scientists are still puzzled about the origin of the comet-shaped
features in the "parka." One possible explanation is that these objects
formed from a collision of slow- and fast-moving gases.
The Eskimo Nebula is about 5,000 light-years from Earth in the constellation
Gemini. The picture was taken Jan. 10 and 11, 2000, with the Wide Field
and Planetary Camera 2. The nebula's glowing gases produce the colors
in this image: nitrogen (red), hydrogen (green), oxygen (blue), and helium
(violet).
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