Astronomers detect life’s building blocks around a young star

 Using the Atacama Large Millimeter/submillimeter Array (ALMA), a team of astronomers led by Abubakar Fadul from the Max Planck Institute for Astronomy (MPIA) has discovered complex organic molecules - including the first tentative detection of ethylene glycol and glycolonitrile - in the protoplanetary disc of the outbursting protostar V883 Orionis. These compounds are considered precursors to the building blocks of life. Comparing different cosmic environments reveals that the abundance and complexity of such molecules increase from star-forming regions to fully evolved planetary systems. This suggests that the seeds of life are assembled in space and are widespread. The findings were published in the Astrophysical Journal Letters today.

Astronomers have discovered complex organic molecules (COMs) in various locations associated with planet and star formation before. COMs are molecules with more than five atoms, at least one of which is carbon. Many of them are considered building blocks of life, such as amino acids and nucleic acids or their precursors. The discovery of 17 COMs in the protoplanetary disc of V883 Orionis, including ethylene glycol and glycolonitrile, provides a long-sought puzzle piece in the evolution of such molecules between the stages preceding and following the formation of stars and their planet-forming discs. Glycolonitrile is a precursor of the amino acids glycine and alanine, as well as the nucleobase adenine.The assembly of prebiotic molecules begins in interstellar space

"Our finding points to a straight line of chemical enrichment and increasing complexity between interstellar clouds and fully evolved planetary systems," said Abubakar Fadul, MPIA

The transition from a cold protostar to a young star surrounded by a disc of dust and gas is accompanied by a violent phase of shocked gas, intense radiation and rapid gas ejection.

Such energetic processes might destroy most of the complex chemistry assembled during the previous stages. Therefore, scientists had laid out a so-called 'reset' scenario, in which most of the chemical compounds required to evolve into life would have to be reproduced in circumstellar discs while forming comets, asteroids, and planets.

"Now it appears the opposite is true," MPIA scientist and co-author Kamber Schwarz points out. "Our results suggest that protoplanetary discs inherit complex molecules from earlier stages, and the formation of complex molecules can continue during the protoplanetary disc stage." Indeed, the period between the energetic protostellar phase and the establishment of a protoplanetary disk would, on its own, be too short for COMs to form in detectable amounts.

As a result, the conditions that predefine biological processes may be widespread rather than being restricted to individual planetary systems.

Astronomers have found the simplest organic molecules, such as methanol, in dense regions of dust and gas that predate the formation of stars. Under favourable conditions, they may even contain complex compounds comprising ethylene glycol, one of the species now discovered in V883 Orionis. "We recently found ethylene glycol could form by UV irradiation of ethanolamine, a molecule that was recently discovered in space," adds Tushar Suhasaria, a co-author and the head of MPIA's Origins of Life Lab. "This finding supports the idea that ethylene glycol could form in those environments but also in later stages of molecular evolution, where UV irradiation is dominant."

Source: ScienceDaily