This is a list of astronomical objects with the spectral type Y. They are a mix of brown dwarfs and planetary-mass objects. They are the coldest such objects in interstellar space and have a temperature around below 500 Kelvin (227°C; 440°F). Only a few are known due to their faint nature. The list is sorted after distance.
Table
JADES-GN-BD-1 and JADES-GN-BD-3 were included as Y-dwarf candiates, but were later found to be consistent with T-dwarfs. Multiple candidate companions found via infrared excess around white dwarfs and one companion (MEAD 62B) were found. Infrared excess candidates can however also be debris disks and a companion can be a background galaxy. Spectroscopy and common proper motion are needed for a confident detection. These are therefore not included, see List of exoplanets around white dwarfs for a list of candidates. A large number of about 50 new candidate Y-dwarf were discovered with SPHEREx. These are only candidates and need confirmation.
Notes
References