Organic Molecule Found in Space
Scientists detect amino acetonitrile near the centre of our Milky Way
Researchers from the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn have detected for the first time a molecule closely related to an amino acid: amino acetonitrile. The organic molecule 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 (Astronomy & Astrophysics, in press).
Figure 1: Amino acetonitrile (NH2CH2CN)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.
Starting from 1965, more than 140 molecular species have been detected in space, in interstellar clouds as well as in circumstellar envelopes. A large fraction of these molecules is organic or carbon-based. A lot of attention is given to the quest for 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 (NH2CH2COOH), 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 (NH2CH2CN), probably a direct precursor of glycine.
“Still, we were finally able to assign 51 very weak lines to the molecule amino acetonitrile” says Arnaud Belloche, scientist at the Max Planck institute and first author of the research paper. This result was confirmed at 10 times higher spatial resolution with two radiotelescope arrays, the IRAM Plateau de Bure interferometer in France and the Australia Telescope Compact Array. These observations showed that all the candidate lines were emitted from the same position in the “Large Molecule Heimat”, “a strong proof of the reliability of our identification”.
“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. We already have several candidates!”, says Karl Menten, director at the Max Planck Institute for Radioastronomy and head of the “Millimeter and Submillimeter Astronomy” research group.
Amino acids are the building blocks of life and finding amino acetonitrile gets us closer to finding amino acids as well as a step closer to understanding where at least some of the amino acids that formed life on earth came from.
