Berlin, March 27 : Scientists have detected for the first time an organic molecule closely related to an amino acid near the centre of our Milky Way.
The organic molecule, known as "amino acetonitrile", was found with a 30-metre radiotelescope in Spain and two radio interferometers in France and Australia in the "Large Molecule Heimat", a giant gas cloud near the galactic centre in the constellation Sagittarius.
The " Large Molecule Heimat " is a very dense, hot gas clump within the star forming region Sagittarius B2.
In this source of only 0,3 light-year diameter, which is heated by a deeply embedded newly formed star, most of the interstellar molecules known to date have been found, including the most complex ones such as ethyl alcohol, formaldehyde, formic acid, acetic acid, glycol aldehyde (a basic sugar), and ethylene glycol.
In all space observations, scientists give the most importance to the detection of so-called "bio" molecules, especially interstellar amino acids.
Amino acids, the building blocks of proteins and therefore key ingredients for the origin of life, have been found in meteorites on Earth, but not yet in interstellar space.
The simplest amino acid, glycine, has long been searched for in the interstellar medium but has so far not been unambiguously detected. Since the search for glycine has turned out to be extremely difficult, a chemically related molecule was searched for, amino acetonitrile, which is probably a direct precursor of glycine.
Scientists from the Max Planck Institute for Radioastronomy in Bonn, Germany, selected the "Large Molecule Heimat", as the source for amino acetonitrile, and investigated a dense forest of 3700 spectral lines from complex molecules with the IRAM 30-metre telescope in Spain.
By analyzing these spectral lines, astronomers can determine the chemical composition of cosmic clouds. The more complex a molecule is, the more possibilities it has to radiate its internal energy. This is the reason why complex molecules emit many spectral lines, which are very weak and therefore difficult to identify in the "line jungle".
"Still, we were finally able to assign 51 very weak lines to the molecule amino acetonitrile," said Arnaud Belloche, scientist at the Max Planck institute and first author of the research paper.
According to Karl Menten, director at the Max Planck Institute for Radioastronomy, "Finding amino acetonitrile has greatly extended our insight into the chemistry of dense, hot star-forming regions. I am sure we will be able to identify in the future many new, even more complex organic molecules in the interstellar gas."