Astronomers Find 'Odd Surplus' of Brown Dwarfs; Origin a Mystery
Astronomers have discovered more than two dozen previously unknown failed stars, otherwise known as brown dwarfs, including "one of the puniest free-floating objects known."
Astronomers discovered the objects in two young star clusters using Japan's Subaru Telescope in Hawaii and the Very Large Telescope in Chile. The team's findings were presented Tuesday at a scientific conference in Garching, Germany.
One of the brown dwarfs is just six times the mass of Jupiter, setting a record on the "puniest" discovered failed star, the researchers said in a statement.
Scientists have yet to unravel how the mysterious failed stars form.
"Its mass is comparable to those of giant planets, yet it doesn't circle a star. ... How it formed is a mystery," said Aleks Scholz of the Dublin Institute for Advanced Studies in Ireland.
Brown dwarfs are larger than planets but they don't circle a star, and they are too small to trigger the internal nuclear fusion reactions required to become full-fledged stars.
"Our findings suggest once again that objects not much bigger than Jupiter could form the same way as stars do," said Ray Jayawardhana of the University of Toronto, principal investigator of the space survey that found the new brown dwarfs. "In other words, nature appears to have more than one trick up its sleeve for producing planetary mass objects."
Space.com reports the newly found brown dwarfs are all located in two star clusters, NGC 1333 and Rho Ophiuchi. NGC 1333 is about 1,000 light-years from Earth in the Perseus constellation, while Rho Ophiuchi is just 400 light-years away, near the constellations Ophiuchus and Scorpius.
NGC 1333 has an odd surplus of failed stars, harboring half as many brown dwarfs as normal stars, researchers said.
"Brown dwarfs seem to be more common in NGC 1333 than in other young star clusters," said Koraljka Muzic of the University of Toronto, lead author of another upcoming paper announcing the findings. "That difference may be hinting at how different environmental conditions affect their formation."
Scholz will lead the work on the publication of the team's latest findings.