Trigonometric Parallaxes and Proper Motions of 134 Southern Late M, L, and T Dwarfs from the Carnegie Astrometric Planet Search Program

TL;DR

This study provides precise distance and motion measurements for 134 low-mass stars and brown dwarfs, including new data for many objects, refining their properties and identifying nearby young stars and potential brown dwarfs.

Contribution

It presents new and improved trigonometric parallaxes for 134 low-mass stars and brown dwarfs, including the first measurements for some objects, enhancing understanding of their distances and properties.

Findings

38 stars have new parallaxes, 14 within 20 pc

Two objects confirmed as young stars in moving groups

First parallax measurement for GJ 3470, refining its planetary density

Abstract

We report trigonometric parallaxes for 134 low mass stars and brown dwarfs, of which 38 have no previously published measurement and 79 more have improved uncertainties. Our survey targeted nearby targets, so 119 are closer than 30 pc. Of the 38 stars with new parallaxes, 14 are within 20 pc and seven are likely brown dwarfs (spectral types later than L0). These parallaxes are useful for studies of kinematics, multiplicity, and spectrophotometric calibration. Two objects with new parallaxes are confirmed as young stars with membership in nearby young moving groups: LP 870-65 in AB Doradus and G 161-71 in Argus. We also report the first parallax for the planet-hosting star GJ 3470; this allows us to refine the density of its Neptune-mass planet. One T-dwarf, 2MASS J12590470-4336243, previously thought to lie within 4 pc, is found to be at 7.8 pc, and the M-type star 2MASS J01392170-3936088 joins the ranks of nearby stars as it is found to be within 10 pc. Five stars that are over-luminous and/or too red for their spectral types are identified and deserve further study as possible young stars.