| Term: | T dwarfs |
| Definition: |
A type of brown dwarf with an effective temperature between about 1200 K and 500 K, i.e. colder than the preceding type L dwarf. The spectra of T dwarfs are characterized by the presence of methane bands in the near infrared. The presence of these bands, broad H_{2}O features, and H_2 collision-induced absorption radically alter the spectral energy distributions of T dwarfs compared to a black body at the same temperature. Hence near-infrared colors become increasingly blue (J - K ~ 0) as compared to L dwarfs. The first T dwarf, called Gl 229B, was discovered by Nakajima et al. The spectral classification scheme (subtypes T0 to T9) currently used was defined by Burgasser et al. |