Scientists call the individual wavelengths in such a pattern spectral lines, because of their appearance in plots. A specific chemical can produce numerous spectral lines. The exact wavelength of each line can be measured, but that process is quite laborious and challenging. However, without such measurements, it has been difficult to identify many lines seen in astronomical observations. Adding to the difficulty is the fact that the pattern of lines for a particular molecule changes with its temperature.
The breakthrough comes because of new technology that allows scientists to gather and analyze a broad swath of wavelengths at once, both with ALMA and in the laboratory.
"We now can take a sample of a chemical, test it in the laboratory, and get a plot of all its characteristic lines over a large range of wavelengths. We get the whole picture at once," said Frank DeLucia of the Ohio State University (OSU). "We can then model the characteristics of all the lines of a chemical at different temperatures," he added.
Armed with new OSU laboratory data for a few suspected molecules, the scientists then compared the patterns with those produced by observing the star-forming region with ALMA.
"The matchup was amazing," said Sarah Fortman, also from OSU. "Spectral lines that had been unidentified for years suddenly matched our laboratory data, verified the existence of specific molecules, and gave us a new tool to attack the complex spectra from regions in our Galaxy," she added. The first tests were done with ethyl cyanide (CH3CH2CN) because its existence in space was alre
|Contact: Dave Finley|
National Radio Astronomy Observatory