WISE J222055.31−362817.4 (designation abbreviated to WISE 2220−3628) is a brown dwarf of spectral class Y0, located in constellation Grus at approximately 34.2 light-years from Earth.
WISE 2220−3628 was discovered in 2012 by J. Davy Kirkpatrick et al. from data, collected by Wide-field Infrared Survey Explorer (WISE) Earth-orbiting satellite — NASA infrared-wavelength 40 cm (16 in) space telescope, which mission lasted from December 2009 to February 2011. In 2012 Kirkpatrick et al. published a paper in The Astrophysical Journal, where they presented discovery of seven new found by WISE brown dwarfs of spectral type Y, among which also was WISE 2220−3628.
Y-class dwarfs are among the coldest of all brown dwarfs. WISE 2220-3628 was observed with JWST and found to be very similar to CWISEP J1935-1546, with the difference of having no signature of an aurora and no temperature inversion in its atmosphere.
The most accurate distance estimate of WISE 2220−3628 was a trigonometric parallax, published in 2014 by Beichman et al.: 0.136 ± 0.017 arcsec, corresponding to a distance of . Later the parallax measurement was improved revealing a larger distance of about 34 light years.