MPE: New Organic Molecule Discovered in Interstellar Cloud

[bystander]

From Lab to Space: Discovery of a New Organic
Molecule in an Interstellar Molecular Cloud
Max Planck Institute for Extraterrestrial Physics | 2020 Jun 17

The background image shows the Galactic centre as observed at 8 microns by the IRAC4 (Infrared array camera) camera of the NASA Spitzer space telescope. The yellow star indicates the position of the Galactic centre and the cyan star corresponds to the position of the source studied in this work, the molecular cloud G+0.693-0.027. In this region, the molecule propargylimine (HCCCHNH) was detected for the first time. The molecule is represented in the bottom right circle of the figure. Credits: NASA/JPL-Caltech/Spitzer, IRAC4 (8 microns), MPE-CASAC, Víctor M. Rivilla (INAF-Arcetri).

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Laboratory experiments performed at the Centre for Astrochemical Studies (CAS) of the Max Planck Institute for Extraterrestrial Physics (MPE) in Munich, together with astronomical observations conducted by the Italian National Institute of Astrophysics (INAF), lead to the identification of a new molecule in the molecular cloud known as G+0.693-0.027, close to the Galactic centre. The newly discovered molecule is called propargylimine: according to the experts, this chemical species may play a fundamental role in the formation of amino acids, among the key ingredients for life as we know it.

The propargylimine has the chemical formula HCCCHNH and is an unstable compound. It is very difficult to isolate it in the ordinary conditions of the Earth’s atmosphere, but it thrives at low densities and temperatures typical of the interstellar medium. Luca Bizzocchi, the study’s lead author who studied the molecule spectroscopy at MPE, explained: "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".

Every molecule absorbs and emits radiation at certain wavelengths, creating a pattern that uniquely describes it, like human fingerprints. With the aim of unveiling the presence of propargylimine in space, spectroscopic analysis has been performed at the Max Planck laboratories to rebuild the molecule’s “identikit”.

"As a molecule rotates in the interstellar medium it emits photons at very precise frequencies. This information, when combined with data from radio telescopes, allows us to know whether a molecule is present in the molecular clouds, the sites of star and planet formation", continues Bizzocchi. ...

Propargylimine in the Laboratory and in Space: Millimetre-Wave
Spectroscopy and First Detection in the ISM ~ Luca Bizzocchi et al

• arXiv.org > astro-ph > arXiv:2006.08401 > 15 Jun 2020