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

TL;DR

This paper reports the discovery and characterization of a new Y0pec dwarf star, WISE J030449.03-270508.3, which may be older and more metal-poor than previously known Y dwarfs, expanding our understanding of this population.

Contribution

The discovery of a new Y0pec dwarf with spectral features indicating potential metal-poor and older characteristics, extending the known parameter space of Y dwarfs.

Findings

Likely distance of 10-17 parsecs.

Spectral features suggest high gravity and low metallicity.

Possible age around 10 billion years.

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.