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In a gas cloud close to the galactic center researchers have discovered a new molecule called propargylimine. This little molecule is an unstable compound and doesn’t last long in the Earth’s atmosphere, but the low-density conditions of an interstellar cloud are ideal for its formation.
The molecule is made of carbon and nitrogen and could be a precursor to amino acids, the building blocks of proteins. The work, accepted for publication in Astronomy & Astrophysics, produced the first estimate of how much propargylimine is present in the molecular cloud known as G+0.693-0.027.
"The peculiarity of this chemical species lays in its carbon-nitrogen double bond, which gives it a high reactivity. With this double bond, it becomes a fundamental constituent of the chemical chains that lead from the simplest and most abundant molecules in space containing carbon and nitrogen – for example formaldehyde (H2CO) and ammonia (NH3), respectively – to the more complex amino acids, the fundamental building blocks of terrestrial biology," lead author Dr Luca Bizzocchi, from the Max Planck Institute in Extraterrestrial Physics (MPE), said in a statement.
Amino acids have been found in space before. For example, the European Space Agency’s Rosetta mission discovered glycine in the tail of comet 67P Churyumov-Gerasimenko. Molecules such as propargylamine are often seen as intermediate steps in the production of amino acids, and for this reason, researchers use a technique known as molecular spectroscopy to look for it in space. As molecules vibrate and rotate, they emit electromagnetic radiation at specific wavelengths. Researchers look for these emissions in the lab, where they can create a library of them and then match them with what it is seen in outer space.
"High precision molecular spectroscopy is one of our group’s goals," explained co-author Dr Paola Caselli, the director of the Center for Astrochemical Studies at MPE. "Only with high precision measurements of the frequencies of interstellar molecules can we use such molecules as powerful diagnostic tools of the physical and chemical evolution of interstellar clouds, where stellar systems like our own form."
Given that it is the first discovery of propargylimine in outer space, there has not been much discussion yet about how this molecule forms. The scientists propose a few possible ways, highlighting that all the possible parent chemicals are up to 100 times more common in G+0.693-0.027. Propargylamine is just one of the many complex carbon-based molecules that can form in the depths of space.
