恒星系统中首次发现复杂有机分子

For the first time, astronomers² have detected the presence of complex organic molecules⁴, the building blocks of life, in a protoplanetary disc surrounding a young star. The discovery, made with the Atacama Large Millimeter/submillimeter Array (ALMA), reaffirms that the conditions that spawned⁵ the Earth and Sun are not unique in the Universe. The results are published in the 9 April 2015 issue of the journal Nature. The new ALMA observations reveal that the protoplanetary disc surrounding the young star MWC 480 [1] contains large amounts of methyl cyanide (CH3CN), a complex carbon-based molecule³. 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, in a region that astronomers believe is analogous⁶ to the Kuiper Belt -- the realm of icy planetesimals and comets in our own Solar System beyond Neptune⁷.

 

Comets retain a pristine⁸ record of the early chemistry of the Solar System, from the period of planet formation. Comets and asteroids⁹ from the outer Solar System are thought to have seeded the young Earth with water and organic molecules, helping¹⁰ set the stage for the development of primordial¹¹ life.

 

"Studies of comets and asteroids show that the solar nebula¹² that spawned the Sun and planets was rich in water and complex organic compounds," noted¹³ Karin Öberg, an astronomer¹ with the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, USA, and lead author of the new paper.

 

"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." This is particularly intriguing¹⁴, Öberg notes, since the molecules found in MWC 480 are also found in similar concentrations in the Solar System's comets.

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