New alcohol added to space-stuff catalog.

Astrochemists have discovered another organic chemical in the same region of space where other researchers had identified the first extraterrestrial sugar (SN: 6/24/00, p. 405). On Earth, the alcohol is used to make packaging polymers.

The finding of space-based molecules such as sugar and the newly identified vinyl alcohol could help researchers determine how complex molecules first formed in the cosmos, says Barry Turner of the National Radio Astronomy Observatory in Char lottesville, Va. The findings will appear in a forthcoming issue of ASTROPHYSICAL JOURNAL LETTERS.

Turner and A.J. Apponi of the University of Arizona's Steward Observatory in Tucson found vinyl alcohol near the center of the Milky Way in the gas and dust cloud Sagittarius B2. The astrochemists used the 12 Meter Telescope on Kitt Peak near Tucson to detect the molecule's characteristic radio emissions.

"Scientists understand these regions of space very poorly," says Eric Herbst of Ohio State University in Columbus. "The more data we have, the better," he says.

Researchers say that most extraterrestrial molecules form when atoms and small molecules collide in interstellar gas clouds. But such reactions can't efficiently produce molecules with the modest complexity of vinyl alcohol, which has seven atoms, says Lewis E. Snyder of the University of Illinois at Urbana-Champaign. Instead, many astronomers suspect that such molecules form on dust grains.

Vinyl alcohol could offer extra insight into space chemistry because it's part of a molecular trio in which the other members already have been found in space, says Turner. Acetaldehyde, ethylene oxide, and vinyl alcohol are isomers--they have the same atoms but in different arrangements.

"I think it's becoming clearer that isomerization in space is important" for understanding extraterrestrial chemistry, notes Jan M. Hollis of NASA's Goddard Space Flight Center in Greenbelt, Md. When he and his colleagues found sugar in Sagittarius B2 last year, that molecule completed the first known cosmic isomeric triplet. The other members are acetic acid and methyl formate, already known space residents.

Finding the last member of an isomer set is "like completing the inventory," notes Steven Charnley of NASA's Ames Research Center in Mountain View, Calif. Understanding how such isomers form in space could help researchers learn how even larger molecules form.

Snyder says he's particularly interested in whether space chemistry can produce complex molecules that could have jump-started life on Earth.