Young star system found to be host to organic molecules

Image depicting a protoplanetary disk populated with organic molecules.
Image montage by Kerry Hebden. Based on original imagery by Wikimedia.

Scientists using the Atacama Large Millimeter/submillimeter Array have found a complex carbon-based molecule in a protoplanetary disc around a young star – in quantities enough to fill all of Earth’s oceans – hinting that prebiotic chemistry is indeed universal and not limited to our Solar System.

Methyl cyanide (CH3CN), along with hydrogen cyanide (HCN) were both detected in the cold, outer regions of the nascent disc surrounding MWC 480, a million-year-old protostar at the heart of the system. These species are of particular interest as molecules such as cyanides contain carbon-nitrogen bonds, pathways that assist in the production of amino acids – the structural elements from which proteins are built.

“From the study of exoplanets, we know the Solar System isn’t unique in its number of planets or abundance of water,” says lead author of the new paper, Karin Öberg, an astronomer with the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, USA. “We now have evidence that this same chemistry exists elsewhere in the Universe, in regions that could form solar systems not unlike our own.”

The molecules found around MWC 480 were detected in a zone analogous to our own Kuiper Belt, the home of comets and ice-laden objects orbiting beyond Neptune and intriguingly, these type of molecules are also found in similar concentrations in our own solar system’s comets. It is thought that comets are the remnants left over from the formation of the Solar System, frozen records of the conditions in this early epoch. As the planets evolved, it is possible that comets (and asteroids) from these outer regions brought water to Earth, along with organic molecules. If this is the case, then these molecules could have helped life to get established on Earth.

But what are the chances of these molecules surviving the turbulent conditions of this infant disc, as it matures to an established exo-system? As such a large abundance of these molecules were found, more than would be found in interstellar clouds, researchers hypothesise that these species are being produced very efficiently in the protoplanetary disc and on a relatively fast timescale. This rapid formation is crucial in ensuring their survival. It is likely therefore, that these molecules could be sequestered into objects for later dispersal around the evolving exo-system, possible seeding life elsewhere in the Universe in a similar process suggested to have occurred in our own Solar System.