UHerts:Red skies discovered on extreme brown dwarf

[MargaritaMc]

Red skies discovered on extreme brown dwarf
February 2014

A peculiar example of a celestial body, known as a brown dwarf, with unusually red skies has been discovered by a team of astronomers from the University of Hertfordshire’s Centre for Astrophysics Research.

Brown dwarfs straddle the line between stars and planets. They are too big to be considered as planets; yet they do not have sufficient material to fuse hydrogen in their cores to fully develop into stars. They are midway in mass between stars, like our Sun, and giant planets, like Jupiter and Saturn. Sometimes described as failed stars, they do not have an internal source of energy – so they are cold and very faint, and keep on cooling over time.

Very thick layer of clouds

The brown dwarf, named ULAS J222711-004547, caught the researchers' attention for its extremely red appearance compared to "normal" brown dwarfs. Further observations with the VLT (Very Large Telescope) in Chile and the use of an innovative data analysis technique have shown that the reason for its peculiarity is the presence of a very thick layer of clouds in its upper atmosphere.

Federico Marocco, who led the research team from the University of Hertfordshire, said: "These are not the type of clouds that we are used to seeing on Earth. The thick clouds on this particular brown dwarf are mostly made of mineral dust, like enstatite and corundum.
"Not only have we been able to infer their presence, but we have also been able to estimate the size of the dust grains in the clouds."

Read more at:
http://www.herts.ac.uk/about-us/news/20 ... rown-dwarf

The paper, "The extremely red L dwarf ULAS J222711−004547 - dominated by dust", is published in the Monthly Notices of the Royal Astronomical Society by Oxford University Press
http://mnras.oxfordjournals.org/lookup/ ... as/stt2463

[MargaritaMc]

This astrobite relates to another brown dwarf study*, but I'm posting it on this thread as I think that it provides useful background information about the techniques used to measure the atmosphere of brown dwarfs.

http://astrobites.org/2014/02/15/cloudy ... -monoxide/

*http://arxiv.org/abs/1401.8145 A global cloud map of the nearest known brown dwarf, Ian Crossfield et al.