Y dwarf
Videos
An object with a spectral type Y is either a brown dwarf or a free-floating planetary-mass object. They have temperatures below around 500 Kelvin and are colder than T-dwarfs. Y-dwarfs have a similar
Artist's impression of a Y-type brown dwarf.
James Webb Space Telescope images, showing the movement of WISE 0855-0714, the coldest Y-dwarf
Spectrum of WISE 0359−5401 with JWST, showing different molecular absorption bands.
Aurora in CWISEP J1935-1546 detected by its methane emission
T dwarf
Videos
An object with the spectral type T is either a brown dwarf or a young free-floating planetary-mass object. A directly imaged exoplanet with a young age can also be a T-dwarf. T dwarfs are colder than
Y dwarf
…is either a brown dwarf or a free-floating planetary-mass object. They have temperatures below around 500 Kelvin (227°C; 440°F) and are colder than T-dwarfs. Y-dwarfs have a similar spectrum when compared to the giant planet Jupiter. When the spectral classes of L dwarfs and T dwarfs were defined it was…
Spectra of mid to late T-dwarfs, showing absorption due to methane, water vapor, CIA hydrogen and potassium