Discovery of a new Y dwarf: WISE J030449.03-270508.3

Pinfield, D. J.; Gromadzki, M.; Leggett, S. K.; Gomes, J.; Lodieu, N.; Kurtev, R.; Day-Jones, A. C.; Ruiz, M. T.; Cook, N. J.; Morley, C. V.; Marley, M. S.; Marocco, F.; Smart, R. L.; Jones, H. R. A.; Lucas, P. W.; Beletsky, Y.; Ivanov, V. D.; Burningham, B.; Jenkins, J. S.; Cardoso, C.; Frith, J.; Clarke, J. R. A.; Galvez-Ortiz, M. C.; Zhang, Z.
2014
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
DOI
10.1093/mnras/stu1540
We present a new Y dwarf, WISE J030449.03-270508.3, confirmed from a candidate sample designed to pick out low-temperature objects from the Wide-field Infrared Survey Explorer (WISE) data base. The new object is typed Y0pec following a visual comparison with spectral standards, and lies at a likely distance of 10-17 pc. Its tangential velocity suggests thin disc membership, but it shows some spectral characteristics that suggest that it may be metal poor and/or older than previously identified Y0 dwarfs. Based on trends seen for warmer late-type T dwarfs, the Y-band flux peak morphology is indicative of sub-solar metallicity, and the enhanced red wing of the J-band flux peak offers evidence for high gravity and/or low metallicity (with associated model trends suggesting an age closer to similar to 10 Gyr and mass in the range 0.02-0.03 M-circle dot). This object may thus be extending the population parameter space of the known Y0 dwarfs.