WISE J0304−2705 (WISE J030449.03−270508.3) is a Y-dwarf discovered in 2014.
The object was first identified from data of the Wide-field Infrared Survey Explorer in 2014. Follow-up observation with Gemini South obtained a spectrum of the object. The spectral type was found to be Y0pec, with pec standing for peculiar. The object shows a Y-band and J-band morphology indicative of sub-solar metallicity. Alternatively the J-band morphology could be explained by high gravity. This might indicate an old age of about 10 Gyr and a mass of 21−31 . A later analysis pointed out that metallicity might not be the only cause for its unusual color.