Complex Organic Molecules Discovered in Infant Star System
Complex organic molecules, the building blocks of life, have been discovered in an infant star system for the first time, according to new research.
Thanks to observations from the Atacama Large Millimeter/submillimeter Array (ALMA) telescope, astronomers have added to growing evidence that the conditions that spawned the Earth and Sun are not unique in the Universe.
The findings were published in the journal Nature.
The discovery came from the protoplanetary disc surrounding the young star MWC 480 , which, as it turns out, contains large amounts of methyl cyanide (CH3CN) - a complex carbon-based molecule. In fact, there is enough methyl cyanide around MWC 480 to fill all of Earth's oceans.
Both this molecule and its simpler cousin, hydrogen cyanide (HCN), were found in the cold outer reaches of the star's newly formed disc, an area that astronomers believe is similar to the Kuiper Belt - the region of icy planetesimals and comets in our own solar system beyond Neptune.
Comets retain a pristine record of the early chemistry of the solar system, from the time when the planets first formed. It is believed that water and organic molecules on Earth today originated from comets and asteroids from the outer solar system, helping set the stage for the development of primordial life.
"Studies of comets and asteroids show that the solar nebula that spawned the Sun and planets was rich in water and complex organic compounds," lead author and astronomer Karin Öberg noted in a news release. "We now have even better evidence that this same chemistry exists elsewhere in the Universe, in regions that could form solar systems not unlike our own."
Interestingly, the molecules found in MWC 480 are also found in similar concentrations in our own solar system's comets. (Scroll to read on...)
The star MWC 480, which is about twice as massive as the Sun and only about one million years old, is located 455 light-years away in the Taurus star-forming region. Its surrounding disc is in the very early stages of development, and has yet to reveal any obvious signs of planet formation.
Astronomers have known for some time that cold, dark interstellar clouds of dust and gas, as seen in this protoplanetary disc, are hotspots for complex organic molecules - including a group of molecules known as cyanides.
Cyanides, especially methyl cyanide, are important because they contain carbon-nitrogen bonds that are critical for the formation of amino acids - the precursors to proteins and fundamental building blocks of life.
However, until now, scientists weren't sure if these same complex organic molecules could form and survive in the energetic environment of a newly forming solar system, where shocks and radiation can easily break chemical bonds. That's why this newest discovery, thanks to ALMA's high-resolution observations, comes as a welcomed surprise.
Based on the findings, it turns out that these molecules not only survive, but flourish.
What's more, the methyl cyanide molecules detected are much more abundant than would be found in interstellar clouds, meaning protoplanetary discs are able to form complex organic molecules both quickly and efficiently.
"From the study of exoplanets, we know the solar system isn't unique in its number of planets or abundance of water," Öberg concluded. "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."
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