Over two dozen new free-floating brown dwarfs (sometimes described as failed stars), including a lightweight youngster only about six times heavier than Jupiter, residing inside two young star clusters have been discovered by astronomers.
The details of the discovery were presented on Tuesday, at a scientific conference in Garching, Germany and will be published in two forthcoming papers in Astrophysical Journal.
Brown dwarfs are sub-stellar objects that are classified as being in between stars and planets. They glow brightly, from the heat of formation, when young. However, as they cool down, they end up with planet-like atmospheres. Scientists believe that most of them may have formed like stars, isolated from contracting gas clouds. Some of the smaller bodies, however, may have formed like planets around a star and were later ejected.
The researchers said that they hoped the findings could help astronomers better understand how failed stars form in the first place.
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.
Deep images of the NGC 1333 and rho Ophiuchi star clusters, from with the Subaru Telescope in Hawaii, at both optical and infrared wavelengths, were taken by the astronomers. The team then identified the candidate brown dwarfs from the very red colors and confirmed their findings with spectra taken at Subaru and the Very Large Telescope (VLT) in Chile.
The six-Jupiter-mass brown dwarf found in the NGC 1333 cluster is one of the least massive free-floating objects known. Several other newly identified brown dwarfs in both NGC 1333 and rho Ophiuchi clusters have masses below 20 times that of Jupiter. NGC 1333 has an odd surplus of failed stars, harboring half as many brown dwarfs as normal stars, researchers said.