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Brown Dwarf Gliese 229B - Hubble Space Telescope image
Click on image for full size
Hubble Space Telescope image (STScI/AURA)

Gliese 229b - Failed Star

What's in a Name: The 229th entry in the Gliese catalog of stars within 25 parsecs of the Sun (originally published in 1969). "B" means the secondary star in a binary system.
Claim to Fame: First proven detection of a brown dwarf (an object too hot to be a planet but too cool to become a star - only 1300o F or 704o C)
Type of Star: Brown dwarf orbiting a red dwarf star. Shining from energy generated by gravitational contraction, not through nuclear reactions like stars.
How Far Away: 18 light years
How Big: 20 - 50 times as massive as Jupiter (0.02 - 0.05 times the solar mass). Approximately the size of Jupiter
How Bright: 1/100,000 of the sun's luminosity
Where to View: Located in the constellation Lepus, the Hare. Orion's sword points towards Lepus.
When to View:Only visible in large telescopes. Lepus best viewed January - March

Last modified June 15, 2005 by Travis Metcalfe.

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