Discovery Of 'MISSING LINK' Brown Dwarf

An Artist's concept of a Y-class brown dwarf

The Y-class brown dwarfs, till now thought to be a theoretical class and the 'missing link' between the largest planets and the smallest stars, has been recently discovered by NASA's Wide-field Infrared Survey Explorer (WISE).


Brown dwarfs' formation is really an interesting one. Similar to the star construction process is the formation of a brown dwarf, the difference being that when the mass of the nebula which is undergoing gravitational collapse is not enough to trigger a sustained nuclear fusion process in the core (which would have powered a star) and a brown dwarf is born which might have had nuclear fusion in its core for a short period. Because of such an origin it is often termed as a "failed star". These celestial bodies have a gaseous atmosphere like huge planets instead of hot plasma of stars but the atmosphere is constantly driven by convective currents from the hot core due to which the chemicals in the atmosphere do not settle down and do not differentiate with height, a thing common with stars.

Comparison of brown dwarfs by their special type

 However, astronomers classify these 'failed stars' by their special type (a scale of letters assigned to the luminosity of the stars) which relates to their  temperature which determines their EM emissions. Till recent dates the brown dwarfs of spectral class "T" were confirmed to be the coolest existing ones, which radiated in infrared  wavelengths with a temperature of 225 degrees C, but now with sophisticated infrared space telescopes like WISE, Y-class brown dwarfs have been discovered. WISE has spotted six Y-class brown dwarfs close to our sun(within 40 light years distance), with one, WISE 1541-2250, being only 9 light years away.However the most remarkable discovery of WISE is brown dwarf at room temperature, 25 degrees Celsius and is named WISE 1828+2650. Davy Kirkpatrick, a science team member said this regard-"The brown dwarfs we were turning up before this discovery were more like the temperature of your oven."

Well, after this discovery by WISE, studies by NASA's Spitzer Space Telescope and the Hubble Space Telescope would be carried out to discover more mysteries about these "failed stars". In my opinion, these dwarfs have many more mysteries which are yet to be discovered to better understand the difference in process of formation of stars and planets and what causes the differences.


[Via DiscoveryNews(www.discovery.com)]

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