'Rogue planet' spotted 100 light-years away (brown dwarf, Jupiter, new, find)

[Baldrick]

Interesting.

BBC News - 'Rogue planet' spotted 100 light-years away

Astronomers have spotted a "rogue planet" - wandering the cosmos without a star to orbit - 100 light-years away.
Recent finds of such planets have suggested that they may be common, but candidates have eluded close study.
The proximity of the new rogue planet has allowed astronomers to guess its age: a comparatively young 50-120 million years old.
The planet, dubbed CFBDSIR2149-0403, is outlined in a paper posted online to appear in Astronomy and Astrophysics.

[Glitch]

Originally Posted by Baldrick

Interesting.

BBC News - 'Rogue planet' spotted 100 light-years away

Actually, it is the planet's proximity to the AB Doradus Moving Group (ABDMG), a nearby star cluster, that allows astronomers to guess its age, metallicity, and density. They also gave it a spectral type of T7/T7.5 which makes it a T Dwarf or Brown Dwarf, but well under the 13 Jupiter masses required to burn deuterium.

They still do not have a parallax for CFBDSIR2149 yet. They used a combination of redshift and the distance to the ABDMG as an estimate of its distance. Spectral analysis shows it to be a low density Brown Dwarf, with a gravity estimated to be between 3.75 and 4.0 G. The spectrum also indicates its age to be between 20 and 200 million years old, however, because there is an 87% probability that it is a member of the ABDMG which is known to be younger than 150 million years, they are claiming the rogue planet is between 20 and 150 million years old, with a 95% probability that the Brown Dwarf is younger than 150 million years.

Source: http://arxiv.org/pdf/1210.0305v1.pdf