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

Authors :: 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.
Publication Year :: 2014
Abstract: 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 WISE database. 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 disk membership, but it shows some spectral characteristics that suggest 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 ~10 Gyr and mass in the range 0.02-0.03 Mo). This object may thus be extending the population parameter-space of the known Y0 dwarfs.<br />Comment: 10 pages, 6 figures, accepted for publication in MNRAS