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Hubble images of dying stars force cosmic reconsideration

planetary nebula planetary nebula
Planetary nebulae
 
icon VXtreme Video
NASA scientists speak about the latest Hubble pictures
  • Segment 1 (16 minutes)
  • Segment 2 (22 minutes)
  • icon  Sound
    Dr. Bruce Balick explains what the new pictures mean to scientists like himself
  • 241K/21 sec. AIFF format
  • 241K/21 sec. WAV format
  • December 17, 1997
    Web posted at: 5:51 p.m. EST (2251 GMT)

    WASHINGTON (CNN) -- New data gathered by NASA's Hubble Space Telescope reveal that sun-like stars are dying in a much more spectacular way than previously assumed, forcing scientists to rethink their theories on the process.

    The images also cast new light on the final moments of our own sun, which is expected to die about 5 billion years from now.

    Astronomers on Wednesday revealed pictures showing surprisingly intricate glowing patterns spun into space by dying stars. The shapes are reminiscent of pinwheels, lawn sprinkler-style jets, elegant goblet shapes, and rocket engine exhausts.

    The new pictures show the dying stars emitting nebulous gasses in what scientists have dubbed a "final blaze of glory" as a star expands before burning out and becoming what is known as a white dwarf.

    Scientists say that the new Hubble pictures completely overturn the current assumption that sun-like stars gracefully cast off a shell of glowing gas and then settle into a long retirement as a burned-out white dwarf.

    "The first time we looked at the Hubble's breathtaking pictures, we knew that our older and simpler ideas of how these objects are formed had to be overhauled," said Howard Bond of the Space Telescope Science Institute.

    Scientists point out that while the data are predominantly about stars dying, they are also about cosmic rebirth, since the heavier elements (like carbon) cooked in the stars are ejected into interstellar space as raw material for successive generations of stars, planets and, potentially, life.

    Among the surprising new details revealed by the Hubble pictures:

    • Unexplained disks and "donuts" of dust girdling a star, which pinch outflowing gas.
    • Remarkably sharp, inner bubbles of glowing gas blown out by the violently outflowing gasses. This is called a "fast wind" (1,000 miles/sec) ejected during the final stages of a star's death.
    • Jets of high-speed particles that shoot out in opposite directions from a star and plow through surrounding gas, like a garden hose stream hitting a sand pile.
    • Pinwheel patterns formed by symmetrical ejection of material so that intricate structures are mirrored on the opposite side of a star.
    Comparison photo
    This photo compares a ground-based image (L) taken under optimum conditions with a new image from Hubble

    Bond said that these nebulae depicted in the new Hubble pictures also give a preview of our own sun's fate: "Some 5 billion years from now, after the sun has become a red giant and burned the Earth to cinder, it will eject its own beautiful nebula and then fade away as a white dwarf star."

     
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