1,159,665,797 visitors served.
1,159,665,797 visitors served. |
|
 Dictionary/ thesaurus |  Medical dictionary |  Legal dictionary |  Financial dictionary |  Acronyms |  Idioms |  Encyclopedia |  Wikipedia encyclopedia | ? |
brown dwarf |
Also found in: Dictionary/thesaurus, Encyclopedia, Wikipedia | 0.07 sec. |
brown dwarfIn astronomy, object less massive than a star but denser than a planet. Brown dwarfs do not have enough mass to ignite nuclear reactions at their centres, but shine by heat released during their contraction from a gas cloud. Groups of brown dwarfs have been discovered, and some astronomers believe that vast numbers of them exist throughout the Galaxy. The first brown dwarf to be positively identified was Gliese 229B (GI229B), in the constellation Lepus, by US astronomers using images from the Hubble Space Telescope. It is about 50 times as massive as Jupiter but emits only 1% of the radiation of the smallest known star and has a surface temperature of 650°C/1,200°F. Brown dwarfs cannot exist with a mass of greater than 80 times that of Jupiter. How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. |
|
? Mentioned in | ? References in periodicals archive | |
|---|---|---|
Inevitably, note Basri and Brown in the 2006 Annual Review of Earth and Planetary Science, extrasolar planets and brown dwarfs became harder to tell apart. There will still be some brown dwarfs around - lukewarm objects that were too small to become stars. Formation of stars and brown dwarfs, from twice the mass of Jupiter to the mass of the Sun. |
 |
| Free Tools: |
For surfers:
Browser extension |
Word of the Day |
Help
For webmasters: Free content | Linking | Lookup box | Double-click lookup | Partner with us |
|
|---|
Disclaimer |
Privacy policy |
Feedback | Copyright © 2008 Farlex, Inc.
Printer friendly
Cite / link
Email
Feedback
Brown dwarfs
