Well, what exactly is a 'planemo'? Spelling may not be correct.
2006-09-09 02:23:29 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
Brown dwarfs are NOT officially stars - in order to be a star it has to have sustained nuclear fusion at its core, and brown dwarfs never get hot enough in their cores for that. The minimum mass for a star is about 0.08 times the mass of our Sun; less than that it is a brown dwarf. Sometimes brown dwarfs are called failed stars.
The boundary between brown dwarf and planet (the lower end for a brown dwarf, upper end for a planet) is a bit fuzzier. Generally it's considered to be 13 times the mass of Jupiter, where an object can get hot enough for deuterium fusion (which is not sustainable, hense not a star). There was an interesting discussion about this on the Bad Astronomer's blog just the other day, you should check it out: http://www.badastronomy.com/bablog/2006/09/07/the-upper-limit-to-a-planet/
2006-09-09 05:36:23 · answer #1 · answered by kris 6 · 0⤊ 0⤋
Brown dwarves are stars, they need to be at least the mass of 13 Jupiters for the nuclear fusion of deuterium to be able to start within them. (Deuterium is heavy hydrogen, a nucleus with 1 proton and 1 neutron).
2006-09-09 09:33:49 · answer #2 · answered by Anonymous · 0⤊ 0⤋
None: Brown dwarfs are actually stars that are not large enough to produce neuclear fusion and therefore are known as "failed stars". Usually, they are between 0.10 to 0.53 solar masses, and they are found in binary systems.
Planemos are planets actually, and more kinda a abbreviation for PLANEtary Mass Object.
2006-09-09 09:39:07 · answer #3 · answered by iam"A"godofsheep 5 · 0⤊ 0⤋
Too bad about Pluto...at least Uranus is safe, lol.
2006-09-09 09:26:22 · answer #4 · answered by rockerchick82 6 · 0⤊ 1⤋