July 8, 2011

Herschel Detects Cosmic Dust From Supernova

ESA's Herschel Space Observatory has detected cosmic dust from a supernova, adding to the theory that these cosmic fireworks are responsible for its creation.

The astronomers who used Herschel to make the discovery said origin of the dust is important because it plays a crucial role in the formation of stars, particularly billions of years ago when star formation was at its peak.  

"Interestingly, this brand new clue does not come from observations of very distant galaxies, but from one of our closest galactic neighbors," Mikako Matsuura from UCL (University College London), who led a recent study published in the journal Science, said in a statement.

Supernova in the Milky Way galaxy are very rare, but 24 years ago astronomers were treated to one in the Large Magellanic Cloud, a small galaxy about 160,000 light years away.

The star could no longer support its own weight on February 23rd 1987 and it collapsed in a violent supernova.  The resulting shockwave energized material in a disc of gas and dust around the star, and is still traveling outwards at speeds of up to 13 million miles per hour.

The pulse of light from the supernova lit up almost a light year across, which is dozens of times the size of our Solar System, according to the researchers.

The astronomers said new measurements have shown that there is dust in the center of the remnant with a temperature of -418 degrees Fahrenheit.

"We didn't expect to see SN1987A when we planned the survey," Margaret Meixner, from the Space Telescope Science Institute in Baltimore, USA, said in a statement.

"Based on our existing knowledge of dust in supernovae, we could not have anticipated that Herschel would have detected this source. It has definitely been one of the biggest surprises of our project," she adds.

The astronomers said the dust was formed from material that was thrown away from the star in the initial explosion.

"Since no facility comparable to Herschel has existed during the past two decades, we cannot say for certain large amount of cold dust was produced," Matsuura said in a statement.

"But we have proved that a supernova can produce an amount of dust comparable to the mass of the Sun over a period of, at most, a couple of dozen years"”a blink of an eye with respect to a star's lifetime," she adds.

Matt Griffin, from Cardiff University and principal investigator of the SPIRE instrument, said these observations show the power of Herschel for investigating the origin of dust across the ages.

"In turn, this is helping us understand the formation of the stars we see today".


Image Caption: ESA's Herschel infrared observatory has an unprecedented view on the cold universe, bridging the gap between what can be observed from the ground and earlier infrared space missions. Infrared radiation can penetrate the gas and dust clouds that hide objects from optical telescopes, looking deep into star-forming regions, galactic centers and planetary systems. Also cooler objects, such as tiny stars and molecular clouds, even galaxies enshrouded in dust that are barely emitting optical light, can be visible in the infrared. (Credit: C. Carreau, ESA)


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