Spewing superdust.Astronomers have identified a type of supernova supernova, a massive star in the latter stages of stellar evolution that suddenly contracts and then explodes, increasing its energy output as much as a billionfold. Supernovas are the principal distributors of heavy elements throughout the universe; all elements heavier than iron are produced in supernovas. Supernovas also are the principal heat source for interstellar matter and may be a source of cosmic rays. as the main source of space dust, one of the building blocks of stars and planets. A core-collapse supernova--the most common type of exploding star--is triggered when a massive star can no longer resist the power of its own gravity. The star's core implodes To link component pieces to a major assembly. It may also refer to compressing data using a particular technique. Contrast with explode. while its outer layers blast into space. The material that's expelled in this way eventually condenses, and new observations suggest that most cosmic dust comes from this condensation. Angela Speck of the University of Missouri-Columbia and her colleagues used data from visible-light telescopes as well as NASA's infrared Spitzer Space Telescope Spitzer Space Telescope: see infrared astronomy; observatory, orbiting. to study the supernova 2003gd, about 30 million light-years from Earth. Mid-infrared observations of the supernova 499 to 678 days after it appeared indicate that there were large amounts of dust coming from the explosion. Theory suggests that the dust from the supernova may be as heavy as 2 percent of the mass of the sun, Speck and her colleagues report in an upcoming Science. If that rate of dust expulsion is typical, it would suggest that core-collapse supernovas have been major producers of dust throughout cosmic history.--R.C. |
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