CFBDSIRJ214947.2-040308.9 - Free-floating Planetary Mass Object

CFBDSIR2149-0403: a 4-7 Jupiter-mass free-floating planet in the young moving group AB Doradus ?
http://arxiv.org/abs/1210.0305

Quote :

Using the CFBDSIR wide field survey for brown dwarfs, we identified CFBDSIRJ214947.2-040308.9, a late T dwarf with atypically red J-Ks colour. We obtained an X-Shooter spectra, with signal detectable from 0.8 to 2.3 micron, which confirmed a T7 spectral type with an enhanced Ks-band flux indicative of a potentially low-gravity, young, object. The comparison of our near infrared spectrum with atmosphere models, for solar metallicity, shows that CFBDSIRJ214947.2-040308.9 is probably a 650-750 K, log g=3.75-4.0 substellar object. Using evolution models, this translates into a planetary mass object, with an age in the 20-200 Myr range. An independent Bayesian analysis from proper motion measurements results in a 87% probability that this free-floating planet is a member of the 50-120 Myr old AB Doradus moving group, which strengthens the spectroscopic youth diagnosis. By combining our atmospheric characterisation with the age and metallicity constraints arising from the probable membership to the AB Doradus moving group, we find that CFBDSIRJ214947.2-040308.9 is probably a 4-7 Jupiter masses free-floating planet with an effective temperature of ~700K and a log g of ~4.0, typical of the late T-type exoplanets that are targeted by direct imaging. We stress that this object could be used as a benchmark for understanding the physics of the similar T-type exoplanets that will be discovered by the upcoming high contrast imagers.

BBC Article.
http://www.bbc.co.uk/news/science-environment-20309762

Time article.
http://science.time.com/2012/11/14/lost-in-space-a-starless-planet-floats-alone/

ESO press release: http://www.eso.org/public/news/eso1245/

http://www.universetoday.com/134325/strange-loner-planet-gets-astronomers-attention/

« …“We now reject our initial hypothesis that CFBDSIR 2149-0403 would be a member of the AB Doradus moving group,” said Delorme. “This removes the most robust age constraint we had. Though determining that certainly improved our knowledge of the object it also made it more difficult to study, by adding age as a free parameter.”
As for what it is, they narrowed that down to one of two possibilities. Basically, it could be a planetary-mass object with a mass of between 2 and 13 Jupiters that is less than 500 million years in age, or a high metallicity brown dwarf that is between 2 and 40 Jupiter masses and two to three billion years of age. Ultimately, they acknowledge that this uncertainty is due to the fact that our theoretical understanding of cool, low-gravity, and metallicity-enhanced bodies is not be robust enough yet… »


https://arxiv.org/pdf/1703.00843.pdf

CFBDSIR 2149-0403: young isolated planetary-mass object or high-metallicity low-mass brown dwarf ?