WISEA J064750.85-154616.4: a new nearby L/T transition dwarf

TL;DR

This paper reports the discovery and classification of a new nearby L9.5 dwarf and confirms another L8/T transition dwarf, enhancing understanding of the solar neighborhood's brown dwarf population.

Contribution

The study introduces a proper motion search method using WISE and 2MASS data to identify and classify overlooked brown dwarfs in the solar neighborhood.

Findings

Discovered a new L9.5 dwarf at 14 pc

Confirmed a nearby L8/T transition dwarf at 10 pc

Provided spectroscopic distance and velocity estimates for both objects

Abstract

Aims: Our aim is to detect and classify previously overlooked brown dwarfs in the solar neighbourhood. Methods: We performed a proper motion search among bright sources observed with the Wide-field Infrared Survey Explorer (WISE) that are also seen in the Two Micron All Sky Survey (2MASS). Our candidates appear according to their red $J$$-$$K_s$ colours as nearby late-L dwarf candidates. Low-resolution near-infrared (NIR) classification spectroscopy in the $HK$ band allowed us to get spectroscopic distance and tangential velocity estimates. Results: We have discovered a new L9.5 dwarf, WISEA J064750.85-154616.4, at a spectroscopic distance of about 14 pc and with a tangential velocity of about 11 km/s, typical of the Galactic thin disc population. We have confirmed another recently found L/T transition object at about 10 pc, WISEA J140533.13+835030.7, which we classified as L8 (NIR).