Wednesday, 23 May 2012

New brown dwarf discovery

I am working with an international team of astronomers and lead the European network called ‘Rocky Planets around Cool Stars’ (RoPACS). We make interesting discoveries in the field of brown dwarfs and extra-solar planets to provide a better understanding of their nature.

The artist’s impression shows the brown dwarf in the foreground, with its host star in the background. The banded nature of the brown dwarf atmosphere results from its hybrid nature – since brown dwarfs bridge the gap between stars and planets. Credit: J. Pinfield
By searching the most sensitive infrared views of the sky using the new WISE orbiting observatory combined with the UK Infrared and VISTA telescopes, I have identified a new and unusual brown dwarf made of 99% hydrogen and helium with a temperature of just 400 degrees centigrade. Its discovery is a key step in helping distinguish between brown dwarfs and giant planets.

Brown dwarfs form like stars but they are much less massive (they are less than approximately seven per cent of the Sun’s mass), and do not burn hydrogen like the Sun. They just cool and fade over time, reaching planetary-like temperatures after a few billion years.

With a planet-like temperature and a hydrogen-rich atmosphere the new brown dwarf helps us tell giant planets and brown dwarfs apart, since planets (like Jupiter) can display a much richer chemistry. The new brown dwarf is a companion to a Sun-like star and orbits it at a distance of about 2600 times the distance from the Earth to the Sun.

A link to the research paper can be found here.

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