'Origin of life on our planet': Scientists discover the largest molecule ever found in a planet-forming disk

In a new study, scientists have discovered the largest molecule ever found in a planet-forming disk.

Published in the Astronomy and Astrophysics, the study has been conducted by the Leiden University in the Netherlands in collaboration with the European Southern Observatory (ESO).

Using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, researchers have for the first time detected dimethyl ether in a planet-forming disc.

With nine atoms, this is the largest molecule identified in such a disc to date. It is also a precursor of larger organic molecules that can lead to the emergence of life.

"From these results, we can learn more about the origin of life on our planet and therefore get a better idea of the potential for life in other planetary systems," says astronomer Nashanty Brunken.

"It is very exciting to see how these findings fit into the bigger picture."

Dimethyl ether is an organic molecule commonly seen in star-forming clouds, but had never before been found in a planet-forming disc. The researchers also made a tentative detection of methyl formate, a complex molecule similar to dimethyl ether that is also a building block for even larger organic molecules.

"It is really exciting to finally detect these larger molecules in discs. For a while we thought it might not be possible to observe them,” says co-author Alice Booth.

The molecules were found in the planet-forming disc around the young star IRS 48 (also known as Oph-IRS 48) with the help of ALMA.

IRS 48, located 444 light-years away in the constellation Ophiuchus, has been the subject of numerous studies because its disc contains an asymmetric, cashew-nut-shaped “dust trap”. 

This region, which likely formed as a result of a newly born planet or small companion star located between the star and the dust trap, retains large numbers of millimetre-sized dust grains that can come together and grow into kilometre-sized objects like comets, asteroids and potentially even planets.

“What makes this even more exciting is that we now know these larger complex molecules are available to feed forming planets in the disc,” explains Booth. “This was not known before as in most systems these molecules are hidden in the ice.”