Astronomers have reported two of the newly discovered yet oldest known brown dwarfs in our Milky Way Galaxy moving at speeds of 100-200 km/sec.
arXiv, accepted for publication in Monthly Notices of the Royal Astronomical Society (MNRAS)
It is a star-like object that is smaller than a planet and has a mass equivalent to less than one-tenth of the Sun’s mass. Brown dwarfs are unable to produce internal heat through nuclear fusion like stars.
In the present study, scientists used NASA’s Wide-field Infrared Survey Explorer and reported two new brown dwarfs, dubbed WISE 0013+0634 and WISE 0833+0052, in the Pisces and Hydra constellations respectively.
These brown dwarfs are moving at speeds of 100-200 km per second, i.e. a speed significantly faster than other stars and brown dwarfs. These objects are thought to be formed about 10 billion years ago.
Researchers have reported that the atmospheres of these objects are almost entirely made up of hydrogen rather than the more abundant heavier elements seen in younger stars.
“Unlike in other walks of life, the Galaxy’s oldest members move much faster than its younger population,” said lead author Dr David Pinfield from the University of Hertfordshire.
“These two brown dwarfs may be the tip of an iceberg and are an intriguing piece of astronomical archaeology”, Dr Pinfield concluded.
The Galaxy’s ancient brown dwarf population revealed – Royal Astronomical Society (http://goo.gl/P21OvV)
D. J. Pinfield, J. Gomes, A. C. Day-Jones, S. K. Leggett, M. Gromadzki, B. Burningham, M. T. Ruiz, R. Kurtev, T. Cattermole, C. Cardoso, N. Lodieu, J. Faherty, S. Littlefair, R. Smart, M. Irwin, J. R. A. Clarke, L. Smith, P. W. Lucas, M. C. Galvez-Ortiz, J. S. Jenkins, H. R. A. Jones, R. Rebolo, V. J. S. Bejar, & B. Gauza (2013). A deep WISE search for very late type objects and the discovery of two halo/thick-disk T dwarfs: WISE 0013+0634 and WISE 0833+0052 arXiv arXiv: 1308.0495v1