Failed Star
Related Category: Astronomy: General
see brown dwarf.
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FAILED STARS
Some cloud fragments are too small ever to become stars. The giant planet Jupiter is a good example.
A failed star which is not massive enough to ignite thermonuclear fusion in the core. According to stellar models, the maximum mass a brown dwarf can have is .
A bizarre failed star with a record-breaking low surface temperature has been discovered by the United Kingdom Infrared Telescope (UKIRT) in Hawaii, extending the range of extremes the properties of these kinds of objects can possess.
Gliese 229b - Failed Star
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Hubble Space Telescope image (STScI/AURA)
What's in a Name: ...
A brown dwarf is a "failed star" (rather than a planet), but what does that mean? How does one draw the line between the two? Here, astronomers diverge in their opinions as well. "Stars" are objects that shine by nuclear fusion.
Brown dwarfs are sometimes referred to as 'failed stars' since they are are more massive than planets but have insufficient mass to sustain nuclear fusion in their cores.
*Brown dwarfs are a type of failed star. They do not fuse hydrogen and so are technically not considered to be stars.
For example, the Two-Micron All-Sky Survey, which uses infrared cameras, has discovered many nearby "brown dwarfs" -- failed stars that are dark at visible wavelengths but are warm enough to glow in the infrared.
A Large Planet or a Failed Star?
Calculations suggest that Jupiter lacks the mass to initiate hydrogen fusion reactions in its core and become a star by about a factor of 100.
It has been termed by many a "failed star", even though the comparison would be akin to calling an asteroid "a failed Earth". As impressive as it is, extrasolar planets have been discovered with much greater masses.
The Jovian planets are to some extent "failed stars", in that they did not accrete enough mass to trigger nuclear fusion in their cores. Jupiter would have to be 80 times more massive than it is now to be considered even the tiniest of stars.
Brown Dwarf: Either a supermassive planet or a failed star, a brown dwarf has insufficient mass to sustain nuclear fusion.
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A brown dwarf is a "star" whose mass is too small to have nuclear fusion occur at its core (the temperature and pressure at its core are insufficient for fusion) - a failed star. A brown dwarf is not very luminous.
of Jupiter and 75 times the mass of Jupiter to be a brown dwarf. Given that range of masses, the object would not have been able to sustain the fusion of hydrogen like a regular star; thus, many scientists have dubbed brown dwarfs as "failed stars".
This has led some astronomers to term it a "failed star", although it is unclear whether or not the processes involved in the formation of planets like Jupiter are similar to the processes involved in the formation of multiple star systems.
 See also: Dwarf, Brown Dwarf, Planet, Light, Energy
  
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