WISE J085510.83–071442.5 : A new nearby brown dwarf at 2 pc

DISCOVERY OF A ~250 K BROWN DWARF AT 2 pc FROM THE SUN
http://iopscience.iop.org/2041-8205/786/2/L18

Just 2.20^+0.24_-0.20 pc away.

A little more distant than Luhman 16AB (2.02 pc)....

At last, a brown dwarf below the freezing point of water! (Though not too cold for supercooled liquid water.)

Very similar distance to Luhman 16, far as I am aware the 1σ error bars overlap.

Pity it doesn't seem to be a binary, the use of discoverer designation helped in getting Luhman 16 a more memorable name, this one we may be stuck with the WISE designation for a while longer.

NASA's Spitzer, WISE Find Sun's Close, Cold Neighbor

http://www.jpl.nasa.gov/news/news.php?release=2014-127

On arXiv now :
http://arxiv.org/abs/1404.6501

"But scientists estimate it is probably a brown dwarf rather than a planet since brown dwarfs are known to be fairly common."

Scientist said that is more likely to a Brown Dwarf that a Planet,I don't know what is the scientific base they use to state it,because far as I know brown Dwarf are less common than stars,but from microlensing estimates Rogue Planet are fairly common Object ever more common that Brown Dwarfs,they are just too cold to be detect

well this is far as I know... 

"...The newfound coldest brown dwarf is named WISE J085510.83-071442.5. It has a chilly temperature between minus 54 and 9 degrees Fahrenheit (minus 48 to minus 13 degrees Celsius)..."

Too hot for a rogue planet i think (?)

Like Jupiter is 1 Jupiter mass and about -170 Celsius,but WISE J085510.83-071442.5 is about 3 to 10 Jupiter mass so ever if this is a rogue planet I expect be about -48 to -13 Celsius,because it's mass is bigger generate more heating and can still be a planet,well I guess so...

Indications of Water Clouds in the Coldest Known Brown Dwarf
http://arxiv.org/abs/1408.4671

Quote :

We present a deep near-infrared image of the newly discovered brown dwarf WISE J085510.83-071442.5 (W0855) using the FourStar imager at Las Campanas Observatory. Our detection of J3=24.8+0.33 -0.53 (J_MKO=25.0+0.33-0.53) at 2.6sigma -- or equivalently an upper limit of J3 > 23.8 (J_MKO > 24.0) at 5sigma makes W0855 the reddest brown dwarf ever categorized (J_MKO - W2 = 10.984+0.33 - 0.53 at 2.6sigma -- or equivalently an upper limit of J_MKO - W2 > 9.984 at 5sigma) and refines its position on color magnitude diagrams. Comparing the new photometry with chemical equilibrium model atmosphere predictions, we demonstrate that W0855 is 4.5sigma from models using a cloudless atmosphere and well reproduced by partly cloudy models (50%) containing sulfide and water ice clouds. Non-equilibrium chemistry or non-solar metallicity may change predictions, however using currently available model approaches, this is the first candidate outside our own solar system to have direct evidence for water clouds.

Beamín et al. "Temperature constraints on the coldest brown dwarf known WISE 0855-0714"
http://arxiv.org/abs/1408.5424

Combination of several models gives a constraint T_eff < 250 K

Well...

A New Parallax Measurement for the Coldest Known Brown Dwarf
http://arxiv.org/abs/1409.5899

Quote :

...We also show the updated positions of WISE J085510.83-071442.5 in two color-magnitude diagrams. Whereas Faherty and coworkers cited its location in MW2 versus J-W2 as evidence of water clouds, we find that those data can be explained instead by cloudless models that employ non-equilibrium chemistry.

This little thing gets a mention in Laughlin's most recent blog post.

Quote :

It is precisely the object whose prospect seemed so exciting half a lifetime ago. One percent the mass of the Sun. Photosphere plunged into icy deep freeze. Utterly black to the eye, save the occasional faint crackling glow of lightning from deep within.

Though oft overshadowed by exoplanets, the study of brown dwarfs is scarcely any older of a topic. It can be fascinating to skim through the past 15-odd years of relevant literature and observe the changes in understanding; about the warm, cold, familied, lonely, stormy, placid, nearby worlds that quietly make their way through this galaxy, with often nary more that a faint dot on the sky to show they are present at all.

http://news.ucsc.edu/2016/07/coldest-brown-dwarf.html

Astronomers find evidence of water clouds in first spectrum of coldest brown dwarf

and :

http://www.gemini.edu/node/12536

Relevant arXiv paper:

Skemer et al. (2016) "The First Spectrum of the Coldest Brown Dwarf"
http://arxiv.org/abs/1605.04902

Our first taste of what a class II extrasolar giant planet might look like?