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Astronomers Make Find With W.Va. Telescope: ; Group Discovers Molecules Near Center of Galaxy

Posted on: Thursday, 24 June 2004, 06:00 CDT

Astronomers using the Robert C. Byrd Green Bank Telescope have discovered two new molecules in an interstellar cloud of gas and dust near the center of the Milky Way Galaxy.

The discovery, announced Monday by the National Radio Astronomy Observatory's headquarters in Charlottesville, Va., marks the Green Bank Telescope's first detection of new molecules.

The discovery is helping astronomers better understand the complex processes by which large molecules form in space, according to the National Radio Astronomy Observatory.

The eight-atom molecule propenal and the 10-atom molecule propanal were detected 26,000 light years from Earth in an area known as Sagittarius B2. Interstellar clouds such as the one in which the molecules were detected are often many light-years across, and contain the raw material from which new stars are formed.

"These interstellar clouds are the sites of complex chemical reactions that occur over hundreds of thousands or millions of years," said Jan Hollis of NASA's Goddard Space Flight Center in Greenbelt, Md., and a member of the team that discovered the molecules.

"Over time, more and more complex molecules can be formed in these clouds," Hollis said. "At present, however, there is no accepted theory addressing how interstellar molecules containing more than five atoms are formed."

About 130 different molecules, most of them containing a small number of atoms, have been discovered in interstellar clouds.

The molecules found by using the Green Bank Telescope were among a few newly discovered molecules consisting of eight or more atoms. Each new discovery of a molecule helps to define the formation chemistry and nature of interstellar dust grains, believed to be the formation sites for most complex interstellar molecules.

Collaborating with Hollis in the discovery were Anthony Remijan, also of NASA Goddard; Frank Lovas of the National Institute of Standards and Technology in Gaithersburg, Md.; Harald Mollendal of the University of Oslo in Norway, and Philip Jewell, site director at the National Radio Astronomy Observatory at Green Bank.

Their results have been accepted for publication in the Astrophysical Journal of Letters.

Molecules consisting of carbon, hydrogen and oxygen atoms, such as those discovered through the Green Bank observations, are of particular interest to scientists, since they could contain the building blocks for life to begin on a new planet.

Complex molecules in space like those detected with the Green Bank Telescope could have been brought to our solar system by comets and could have played a role in the formation of biologically significant molecules on Earth.

"The Green Bank Telescope can be used to fully explore the possibility that a significant amount of pre-biotic chemistry may occur in space long before it occurs on a newly formed planet," said Remijan.

"Comets form from interstellar clouds and incessantly bombard a newly formed planet early in its history. Craters on our Moon attest to this.

Thus, comets may be the delivery vehicles for organic molecules necessary for life to begin on a new planet."

The large diameter and high precision of the Green Bank Telescope, the world's largest fully steerable radio telescope, "allowed us to study small interstellar clouds that can absorb the radiation from a bright background source," said Jewell.

"The sensitivity and flexibility of the telescope gave us an important new tool for the study of complex interstellar molecules."

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities Inc.

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