For the first time, scientists have detected the presence of complex organic molecules, the building blocks of life, in a rotating disk of dense gas surrounding a young star (infant star system). This finding suggests, again, that the conditions that spawned life on Earth are not unique in the universe.
The discovery, made with the Atacama Large Millimeter/submillimeter Array (ALMA), reveals that the disk surrounding the million-year-old star MWC 480 is filled with the complex carbon-based molecule methyl cyanide (CH3CN).
Both this molecule and its simpler cousin hydrogen cyanide (HCN), were identified in the cold outer reaches of the newly formed star, in a region that astronomers believe is analogous with our solar system’s Kuiper Belt a realm of icy planetesimals and comets beyond Neptune.
Experts believe that asteroids and comets from the outer solar system have seeded the ‘young’ Earth with water and organic molecules that ultimately helped the development of primordial life.
Dr Karin Öberg, an astronomer with the Harvard-Smithsonian Centre for Astrophysics in Massachusetts, said:
Studies of comets and asteroids show that the solar nebula that spawned our sun and planets was rich in water and complex organic compounds.
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 star MWC 480, which is about twice as massive as the sun, is located approximately 455 light-years away in the star-forming region in the constellation Taurus. Its surrounding disk is in an early stages of development while astronomers are yet to detect any obvious signs of planet formation in it.
Astronomers have known for some time that cold, dark interstellar clouds are very efficient factories for complex organic molecules, including a group of molecules known as cyanides. These, and especially methyl cyanide (CH3CN), are important because they contain carbon–nitrogen bonds. These bonds form the basis of amino acids, proteins and life.
What was not known was whether these complex organic molecules commonly survive the shocks and radiation levels found in the newly forming star system where collisions and radiation can easily break chemical bonds.
But now, through ALMA, astronomers know that these molecules not only form and survive, but thrive. These molecules detected by astronomers are much more abundant than would be found in the interstellar clouds. According to the reported in the journal Nature, there is enough methyl cyanide around MWC 480 to fill all of the oceans on Earth.
This tells astronomers that protoplanetary disks are very efficient at forming complex organic molecules that are capable of form them on relatively short timescales.
In addition, these molecules were detected in a relatively serene area of the disc, roughly 4.5-15 billion kilometers from the central star.
Experts speculate that as MWC 480 planetary system continues to evolve, it is likely that organic molecules locked way in comets and other icy bodies will be be ferried closer to environments where conditions may be suitable for life.
From the study of exoplanets, we know our solar system isn’t unique in having rocky planets and an abundance of water.
Dr Oberg added:
Now we know we’re not unique in organic chemistry. Once more, we have learned that we’re not special. From a life in the universe point of view, this is great news.