Brown dwarfs

Definition

Brown dwarfs are celestial objects that are too large to be planets but not massive enough to sustain hydrogen fusion in their cores like true stars. They occupy the mass range between the heaviest gas giant planets and the lightest stars.

5 Must Know Facts For Your Next Test

1. Brown dwarfs have masses between approximately 13 and 80 times that of Jupiter.
2. They emit light primarily in the infrared spectrum due to their relatively low temperatures.
3. Unlike main-sequence stars, brown dwarfs cannot sustain stable hydrogen fusion reactions in their cores.
4. They often form in a similar way to stars, from collapsing clouds of gas and dust, but do not accumulate enough mass to ignite nuclear fusion.
5. Their spectral types range from M, L, T, to Y based on temperature and spectral characteristics.

Review Questions

• What is the primary reason brown dwarfs cannot sustain hydrogen fusion in their cores?
• In what part of the electromagnetic spectrum do brown dwarfs primarily emit light?
• Describe the mass range that distinguishes brown dwarfs from both gas giant planets and true stars.

Related terms

Main-Sequence Stars: Stars that are fusing hydrogen into helium in their cores and lie on the main sequence of the Hertzsprung-Russell diagram.

Gas Giant Planets: Large planets composed mostly of gases such as hydrogen and helium, with a relatively small rocky core.

Spectral Types: Classification system for stars based on their spectra; includes types O, B, A, F, G, K, M for stars and L, T, Y for brown dwarfs.