Discovery of a Possible Early-T Thick-Disk Subdwarf from the AllWISE2 Motion Survey

TL;DR

This paper reports the discovery of a potential early-T subdwarf with thick-disk kinematics, low metallicity, and possible unresolved multiplicity, representing only the second such object identified.

Contribution

It introduces the first identification of an early-T subdwarf from the AllWISE2 Motion Survey, expanding knowledge of low-metallicity subdwarfs.

Findings

Potential early-T subdwarf with thick-disk kinematics

Spectral analysis suggests low metallicity

Possible unresolved multiplicity

Abstract

We have discovered a potential T0 $\pm$ 1 subdwarf from a search for sources in the AllWISE2 Motion Survey that do not have counterparts in surveys at shorter wavelengths. With a tangential velocity of $\sim$170 kms, this object - WISE J071121.36-573634.2 - has kinematics that are consistent with the thick-disk population of the Milky Way. Spectral fits suggest a low-metallicity for this object but also allow for the possibility of unresolved multiplicity. If WISE J0711-5736 is indeed an sdT0 dwarf, it would be only the second early-T subdwarf discovered to date.