Building blocks of life found in infant star system

Astronomers have detected the presence of complex organic molecules - the building blocks of life - in a protoplanetary disc surrounding a young star located 455 light-years away, reaffirming that the conditions that spawned the Earth and Sun are not unique in the universe. The discovery has been published in the journal Nature.

According to Karin Öberg, an astronomer with the Harvard-Smithsonian Center for Astrophysics and lead author of the new study, “Studies of comets and asteroids show that the solar nebula (a large cloud of gas and dust) that spawned the Sun and planets was rich in water and complex organic compounds.” The group of complex organic molecules known as cyanides was particularly important to this process as they contain carbon-nitrogen bonds which are essential for the formation of amino acids - the foundation of proteins and the building blocks of life.

Recent observations made with the Atacama Large Millimeter/submillimeter Array (ALMA) reveal that the protoplanetary disc surrounding the young star MWC 480 contains large amounts of methyl cyanide, along with its simpler cousin hydrogen cyanide. Not only is this the same chemistry as found in our own solar system’s early formation, it is also in similar concentrations and located in a region of the protoplanetary disc which is analogous to our own Kuiper Belt.

Astronomers have known for some time that cold, dark interstellar clouds are very efficient factories for complex organic molecules; however, it has been unclear if these same complex organic molecules commonly form and survive in the energetic environment of a newly forming solar system, where shocks and radiation can easily break chemical bonds. Astronomers have exploited ALMA’s extreme sensitivity to show that these molecules not only survive, but flourish.

The molecules ALMA detected are much more abundant than would be found in interstellar clouds, demonstrating that protoplanetary discs are very efficient at forming complex organic molecules and that they are able to form them on relatively short timescales. Astronomers say it’s likely that the organic molecules locked away in comets and other icy bodies will eventually be ferried to environments more nurturing to life.

“From the study of exoplanets, we know the solar system isn’t unique in its number of planets or abundance of water,” said Öberg. “Now we know we’re not unique in organic chemistry. Once more, we have learnt that we’re not special. From a life-in-the-universe point of view, this is great news.”

Image caption: Artist’s impression of the protoplanetary disc surrounding the young star MWC 480. Image credit: B Saxton (NRAO/AUI/NSF).

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