An international team of astronomers has discovered over two dozen new free-floating brown dwarfs – sometimes described as ‘failed stars’ – including a lightweight youngster only about six times heftier than Jupiter, that reside in two young star clusters.
More interesting is that one cluster contains a surprising surplus of them harbouring half as many of these astronomical oddballs as normal stars.
“Our findings suggest once again that objects not much bigger than Jupiter could form the same way as stars do. In other words, nature appears to have more than one trick up its sleeve for producing planetary mass objects,” said Professor Ray Jayawardhana, Canada Research Chair in Observational Astrophysics at the University of Toronto, who led the team.
Brown dwarfs glow brightly when young, from the heat of formation, but cool down over time and end up with atmospheres that exhibit planet-like characteristics.
Scientists think that most them may have formed like stars, in isolation from contracting gas clouds, but some of the puniest free-floaters may have formed like planets around a star and later been ejected.
The findings come from observations using the Subaru Telescope in Hawaii and the Very Large Telescope (VLT) in Chile during the Substellar Objects in Nearby Young Clusters (SONYC) survey.
Astronomers took extremely deep images of the NGC 1333 and Rho Ophiuchi star clusters with Subaru at both optical and infrared wavelengths.
The team’s findings will be reported in the upcoming Astrophysical Journal.