A search for southern ultracool dwarfs in young moving groups

TL;DR

This study identifies and characterizes 132 ultracool dwarf candidates in the southern hemisphere as potential members of five young moving groups, using photometric, astrometric, and spectroscopic data to assess their membership, ages, and masses.

Contribution

The paper introduces a new sample of ultracool dwarf candidates with confirmed kinematic properties, improving understanding of their ages and metallicities within young moving groups.

Findings

Up to ~75 of the candidates are likely genuine members.

Spectroscopic data constrains distances and space motions.

The sample aids in studying ultracool dwarf evolution and group properties.

Abstract

We associate 132 low-mass ultracool dwarfs in the southern hemisphere as candidate members of five moving groups using photometric and astrometric selection techniques. Of these objects, we present high resolution spectroscopy for seven candidates and combine these with previous measurements from the literature to determine spectral types and radial velocities. We thus constrain distance and space motion spectroscopically, allowing the kinematic membership of the moving groups to be assessed. Possible membership of moving groups has allowed ages and metallicities to be constrained for these objects and evolutionary models have been used to estimate their mass. We estimate that up to ~75 of our candidate moving group members should be genuine, and discuss future work that will confirm and exploit this major new sample.