Characterizing the AB Doradus Moving Group Via High Resolution Spectroscopy and Kinematic Traceback

TL;DR

This study uses high-resolution spectroscopy and kinematic analysis to characterize the AB Doradus moving group, confirming membership, assessing chemical homogeneity, and estimating an age of approximately 125 million years.

Contribution

It provides detailed spectroscopic parameters for proposed members and evaluates their membership and age using multiple models and methods, which is a novel comprehensive approach.

Findings

Average metallicity is [M/H] = -0.03 ± 0.06.

Traceback age of the group is approximately 125 Myrs.

Identified 6 confirmed members and 4 non-members/enigmas.

Abstract

We present a detailed analysis of 10 proposed F and G members of the nearby, young moving group AB Doradus (ABD). Our sample was obtained using the 2.7m telescope at the McDonald Observatory with the coude echelle spectrograph, achieving R $\sim$ 60,000 and S/N $\sim$ 200. We derive spectroscopic T$_{eff}$, log(g), [Fe/H], and microturbulance (v$_{t}$) using a bootstrap method of the TGVIT software resulting in typical errors of 33K in T$_{eff}$, 0.08 dex in log(g), 0.03 dex in [Fe/H], and 0.13 km s$^{-1}$ in v$_{t}$. Characterization of the ABD sample is performed in three ways: (1) Chemical homogeneity, (2) Kinematic Traceback, and (3) Isochrone fitting. We find the average metal abundance is [M/H] = -0.03 $\pm$ 0.06 with a traceback age of 125 Myrs. Our stars were fit to 3 different evolutionary models (Siess et al. 2000, Baraffe et al. 1998, and YREC) and we found the best match to our ABD sample is the YREC [M/H] = -0.1 model. In our sample of 10 stars, we identify 1 star which is a probable non-member, 3 enigmatic stars, and 6 stars with confirmed membership. We also present a list of chemically coherent stars from this study and the Barenfeld et al. (2013) study.