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Astronomers find life's sweet building blocks around young star

August 29, 2012|By Thomas H. Maugh II
  • The Rho Ophiuci star-forming region as seen by NASA's WISE satellite. Astronomers have detected the sugar glycoaldehyde (in circle) in the gas surrounding a star called IRAS 16293-2422 (in box).
The Rho Ophiuci star-forming region as seen by NASA's WISE satellite.… (ESO/L. Cal?ada & NASA/JPL-Caltech/WISE…)

Astronomers have for the first time found a simple sugar, one of the building blocks of life, around a young star. The sugar, called glycoaldehyde, is in the dust disk surrounding the star and would most likely be incorporated into planets as they form.

The finding suggests that at least some of the building blocks of life may have been present when the Earth itself condensed from the dust surrounding our sun, researchers said.

A team headed by astrophysicist Jes K. Jorgensen reported Wednesday in the Astrophysical Journal Letters that it observed the sugar during the preliminary scientific validation studies of the Atacama Large Millimeter/submillimeter Array (ALMA) at the European Southern Observatory in Chile. ALMA is an array of 66 high-precision antennas spread out over distances of as much as 10 miles. It detects radiation with wavelengths in the region of a millimeter or less, which corresponds to wavelengths between infrared light and radio waves.

The star system, called IRAS 16293-2422, is a binary star in the Rho Ophiuchi star-forming region about 400 light-years from Earth. It has a mass similar to the Earth's, but is younger and appears to be in the very early stages of planet formation.

Sugar is a common name for carbohydrates, organic compounds containing carbon, hydrogen and oxygen, with a hydrogen-to-oxygen ratio of 2 to 1. Glycoaldehyde has two atoms of carbon, four of hydrogen and two of oxygen. It can condense into larger sugars, particularly those that are found in RNA, one of the key building blocks of life, Jorgensen said.

Glycoaldehyde has been detected in space twice before, but neither time so near to a young star. "What is really exciting about our findings is that the ALMA observations reveal that the sugar molecules are falling in toward one of the stars of the system," said co-author Cecile Favre of Aarhus University in Copenhagen. "The sugar molecules are not only in the right place to find their way onto a planet, but they are also going in the right direction."

The dust clouds surrounding new stars are extremeley cold, usually around 10 degrees above absolute zero. That causes the sugars and other chemical compounds to freeze on their surface. But as the particles move closer to the star, they are heated, vaporizing some of the sugar molecules, which emit radiation allowing them to be detected by the very sensitive ALMA.

"The complex molecules in the cloud surrounding the newly formed star tell us that the building blocks of life may be among the first formed," Jorgensen said. "One of the big questions is whether it is common that these organic molecules are formed so early in the star and planet formation process -- and how complex they can become before they are incorporated into new planets. This could potentially tell us something about the possibility that life might arise elsewhere and whether precursors to biology are already present before the planets have been formed."


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