Orbit of ultra-cool brown dwarf binary

An international team of astronomers using the world's biggest telescopes have directly measured the mass of an ultra-cool brown dwarf star and its companion star for the first time. Barely the size of the planet Jupiter, the dwarf star weighs in at just 8.5 percent of the mass of our Sun. This is the first ever mass measurement of a dwarf star belonging to a new stellar class of very low mass ultra-cool dwarf stars called L-dwarfs. The observation is a major step towards our understanding of the types of objects that occupy the gap between the lightest stars and the heaviest planets.

This image shows the orbit of the brown dwarf around the ultra-cool L-dwarf. Each red dot on the orbit (in blue) corresponds to one observation made with a ground- or space-based telescope. The observations cover 60% of the whole orbit.


ESA/NASA and Herve Bouy (Max-Planck-Institut für Extraterrestrische Physik/ESO, Germany)

About the Image

Release date:15 June 2004, 15:00
Related releases:heic0410
Size:3000 x 2141 px

About the Object

Name:2MASSW J0746425+2000321
Type:Milky Way : Star : Type : Brown Dwarf
Milky Way : Star : Spectral Type : L
Milky Way : Star : Grouping : Binary

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r.titleScreensize JPEG
108.3 KB

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