# Radial Velocities of Low-mass Candidate TWA Members

## TL;DR

This study uses near-infrared spectra and radial velocity measurements to assess the membership of two low-mass candidates in the TW Hya Association, highlighting the importance of precise spectroscopy for confirming group membership.

## Contribution

It provides new radial velocity data for two candidate members, demonstrating the effectiveness of high-resolution near-infrared spectra in verifying low-mass star memberships in young moving groups.

## Key findings

- TWA 46 is a spectroscopic binary with a low membership probability.
- TWA 47 is likely a true member with high membership probability.
- High-resolution spectra are crucial for accurate group membership validation.

## Abstract

Nearby young moving groups provide unique samples of similar age stars for testing the evolution of physical properties. Incomplete and/or incorrect group membership classifications reduce the usefulness of the group, which we assume to be coeval. With near-infrared spectra of two candidate members of the TW Hya Association, 2MASS J12354615$-$4115531 (TWA 46) and 2MASS J12371238$-$4021480 (TWA 47), we test their membership by adding radial velocity measurements to the literature. We find that 2MASS J12354615$-$4115531 is a close spectroscopic binary system with a center-of-mass radial velocity of -6.5$\pm$3.9 km s$^{-1}$. This radial velocity and a $\textit{Gaia}$ parallax produces a TWA membership probability of 41.9$\%$ using the Banyan $\Sigma$ tool for 2MASS J12354615$-$4115531. The spectrum of 2MASS J12371238$-$4021480 shows that it appears to be a single star with a radial velocity consistent with the TW Hya Association and a membership probability of 99.5$\%$. The reduced probability of TWA 46 as a true member of TWA highlights the importance of high-resolution, near-infrared spectra in validating low-mass moving group members.