Astronomers in Britain report they've discovered a peculiar example of a celestial body known as a brown dwarf, one with unusually red skies.

The brown dwarf, named ULAS J222711-004547, caught the attention of astronomers at the University of Hertfordshire for its extremely red appearance compared to "normal" brown dwarfs.

They report analysis showed the reason for its peculiar color is the presence of a very thick layer of clouds in its upper atmosphere.

"These are not the type of clouds that we are used to seeing on Earth," research leader Federico Marocco said. "The thick clouds on this particular brown dwarf are mostly made of mineral dust, like enstatite and corundum."

Brown dwarfs, falling between stars and planets, are too big to be considered planets yet do not have sufficient material to fuse hydrogen in their cores to fully develop into stars. Sometimes described as failed stars, they are cold and very faint.

The giant planets of the solar system, like Jupiter and Saturn, show various cloud layers including ammonia and hydrogen sulphide as well as water vapor. The atmosphere observed in this reddish brown dwarf is hotter, the researchers said, with water vapor, methane and probably some ammonia but, unusually, dominated by clay-sized mineral particles.

Understanding how such an extreme atmosphere works will help improve understanding of the range of atmospheres that can exist, university researcher Avril Day-Jones said.

"By studying the composition and variability in luminosity and colors of objects like this, we can understand how the weather works on brown dwarfs and how it links to other giant planets," she said.