Scientists find oldest known planetary disc

Astronomers believe they have found the oldest known planet-forming disk — a 45-million-year-old ring of gas and dust that orbits around a young star. Circumstellar discs around red dwarfs like this one are rare to begin with, but this star, called AWI0005x3s, appears to have sustained its disc for an exceptionally long time, according to the study published in The Astrophysical Journal Letters.

“Most discs of this kind fade away in less than 30 million years,” said lead researcher Steven Silverberg from University of Oklahoma in the US. “This particular red dwarf is a candidate member of the Carina stellar association, which would make it around 45 million years old (like the rest of the stars in that group). It’s the oldest red dwarf system with a disc we’ve seen in one of these associations,” Silverberg noted. The discovery relied on citizen scientists from Disk Detective, a project led by NASA’s Goddard Space Flight Center’s Marc Kuchner that is designed to find new circumstellar disks.

“It is surprising to see a circumstellar disc around a star that may be 45 million years old, because we normally expect these discs to dissipate within a few million years,” one of the researchers Jonathan Gagne from Carnegie Institution for Science said.