Six new M-type members of TW Hydrae

<p>Presented at the "<em>19th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun</em>"</p><p>June 6-10, 2016 (Uppsala, Sweden)</p><div> <div> <div> <p>The recent BANYAN All-Sky Survey (BASS, Gagné+15) has proposed several hundred M4-L6 candidate members of nearby young moving groups, including ~30 high-probability (>80%) members of the 10 Myr-old TW Hydrae association (TWA). </p> <p>As these nearby (<70 pc) stars are prime targets for exoplanet direct imaging, we have obtained ANU 2.3-m/WiFeS spectra for 19 BASS TWA candidates. At these spectral types and ages, true members of TWA will show strong Li I 6708Å absorption, and RVs consistent with the association space motion. </p><p>We find that six BASS candidates have undepleted Li abundances consistent with membership in TWA. These new discoveries, as well as two L7 brown dwarfs recently proposed as members (Kellogg +16, Schneider+16), demonstrate that the TWA mass function remains incomplete at low and substellar masses, and more new members likely await discovery in large IR surveys.</p><div><br></div><div><div></div></div> </div> </div>