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A cocktail of chemicals is venting from the oxygen-rich region surrounding one of the most sensitive environmental atmospheres known. Radio astronomers have detected small chemical species, including common salt, hydrogen isocyanide, phosphorus nitride, and protonated carbon monoxide, in the environment around a supergiant star. A score of molecules that could represent the fundamental chemical components of life on earth have been observed by University of Arizona scientists using the world's most sensitive radio telescope, the Arizona Radio Observatory's 10m Submillimeter Telescope (SMT) on Mount Graham. The highly accurate SMT can detect emissions from distant space that are weaker than a typical light bulb. "I don't think anyone would have predicted that VY Canis Majoris is a molecular factory. It was really unexpected," says Arizona chemist Lucy Ziurys, Director of ARO, "Everyone thought that the interesting chemistry in gas clouds around old stars was happening in envelopes around nearer, carbon-rich stars. But when we started looking closely for the first time at an oxygen-rich object, we began finding all these interesting things that weren't supposed to be there." VY Canis Majoris is one of the most luminous infrared objects in the sky. It is a dying star lying about 5000 light years from Earth. Although it is half a million times as bright as the sun and 25 times more massive it is much cooler and so glows mostly in the infrared. Matter is evaporating from this supergiant, which would subsume the orbit of Jupiter, so fast that the star will have vanished within a million years. Ziurys and her colleagues are surveying radio data from VY Canis Majoris and published preliminary findings recently in the journal Nature. Their paper lists a score of chemicals obvserved in the cloud around the supergiant. Until now, astronomers have found very little phosphorus in the outflows from cool stars and have observed only limited ion chemistry. The UA team has discovered that the molecules are not only flowing from the supergiant as a gas sphere around VY Canis Majoris, but also are blasting out as jets through this spherical envelope. According to Ziurys, comets and meteorites dump about 40,000 tonnes of interstellar dust on Earth each year, and provided the source of the carbon from which living things are made. "The origin of organic material on Earth, probably came from interstellar space. So one can say that life's origins really begin in chemistry around objects like VY Canis Majoris." In the 1960s, few scientists believed molecules could survive the harsh environment of space. Ultraviolet radiation supposedly reduced matter to atoms and ions. Today, scientists suggest that at least half the gas in interstellar space within the 33000-light-year inner galaxy is molecular. "Our results provide more evidence that we live in a molecular universe, as opposed to an atomic one," Ziurys says. "This work tells us that the biochemistry of life here on Earth may have been shaped by the chemistry that occurred and still occurs in interstellar space," Ziurys told SpectroscopyNOW Related links:
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Stellar molecular jets |
