Brown Dwarf

[Tiny]

Hello forks
I was doing a project about Brown Dwarf and mind someone tell me what are the major point about BD?
This is the information I found, did I missing any thing?

- In astronomy, most of the astronomer called it a fail star.
- Small core
- Can not fusing H and He
- Lower massive star, which is less than 0.008 Msun
- Faint classes stars (Dim)
- Found in the Halo
- Formed from gas by gravitaional conctraction
- Lower temperature (below 1300 K)
- Cold, can only be observe with infrared telescope
- Some scientist said, they can found solid grains on its atmosphere (surface)
- L and T class star on the H-R diagram
- Element : H, He and 1% metals

[tony873004]

Your list sums it up pretty well. Of course there is lots of literature to read if you want more depth than your summary. Here's a few things I can add:

Some scientists feel that brown dwarfs outnumber stars in the galaxy, and may account for a significant percentage of the galaxy's dark matter.

The lower limit for a brown dwarf is thought to be about 70 jupiter masses, although its the way they form, and not how massive they are that make them brown dwarfs. They form in the same way stars form, but lack enough mass to be a star. Upper mass is .08 sun masses like your list states. Above this, and they can burn hydrogen which would make them a star.

Brown dwarfs were only theorized for many years prior to astronomers actually finding one (I believe 8-10 years ago)

Most brown dwarfs are probably part of binary brown dwarf systems, just like most stars are binary.

Brown dwarfs probably have planets.

[Tim Thompson]

The general consensus amongst astronomers is that brown dwarfs inhabit the range of masses from 0.08 solar masses (about 80 Jupiter masses), down to about 0.013 solar masses (about 13 Jupiter masses). The high end of this mass range is the minimum mass required to provide enough compressional heating to initiate proton-proton fusion, the nuclear reaction that powers main sequence stars. The low end of this mass range is the minimum mass required to provide enough compressional heating to initiate deuteron-deuteron fusion. A deuteron is a proton with a neutron attached. They emit far less energy when they fuse than do bare protons, and they do it at a far lower temperature (proton-proton fusion requires about 3,000,000 Kelvins, deuteron fusion much less, though I can't find a reliable number). Anything less than about 13 Jupiter masses is too cool at the center even to fuse deuterons, and that's that maximum mass for a planet. So jupiter is not just a "failed star", as some like to say, it's a "failed brown dwarf".

• Hunting Brown Dwarfs
• M dwarfs, L dwarfs and T dwarfs
• Gliese 229B - The first discovered brown dwarf

[Tiny]

Thanks ^_^ Tony873004 and Tim Thompson, I think that's enough information... thx