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NASA's
Hubble Space Telescope has unveiled a of variety shapes, structures,
and fireworks that accompany the birth and death of stars.
Hubble images of newly forming stars reveal blowtorch-like
jets of hot gas streaming from deep within the disks around
the stars. Possibly shaped into long slender streamers by
magnetic fields, these jets are an "exhaust product" of star
formation. They travel across space for billions of miles
before slamming into material in the star's vicinity. In dramatic
images, Hubble has shown the effects of very massive young
stars on their surrounding nebulae. The astronomical equivalent
of a hurricane, the intense flow of visible and ultraviolet
radiation from an exceptionally massive young star eats into
surrounding clouds of cold hydrogen gas, laced with dust.
This helps trigger a firestorm of star birth in the neighborhood
around the star.
Hubble
has produced a dazzling array of images of colorful shells
of gas blasted into space by dying stars. These intricate
structures are "fossil evidence," showing that the final stages
of stars' lives are more complex than once thought. An aging
star sheds its outer layers of gas through stellar winds.
Late in a star's life, these winds become more like a gale
and consequently sculpt strikingly complex shapes. When massive
stars die, they don't die as quietly as lighter-weight stars.
They end their lives with mammoth explosions. The Hubble has
been keeping an "eye" on one such nearby explosion, Supernova
1987A. The star's self-destruction was first seen nearly 12
years ago on February 23, 1987 by a ground-based telescope.
In July 1997 the Hubble telescope's imaging spectrograph captured
the first images of material ejected by the exploding star
ramming into an inner ring around the dying object. Shocked
by the 40-million-mile-per-hour sledgehammer blow, a 100-billion-mile-wide
knot of gas in a piece of the ring has already begun to "light
up," as its temperature surges from a few thousand degrees
to a million degrees Fahrenheit. By analyzing this glowing
ring, astronomers may find clues to the final years of the
doomed star's existence.
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