New Members of the Scorpius Centaurus Complex and Ages of its sub-regions

TL;DR

This study spectroscopically identified new members of the Scorpius Centaurus complex and estimated their ages using lithium absorption lines, finding they are younger (~10 Myr) than previously thought, which suggests calibration issues in age-dating methods.

Contribution

It provides new spectroscopic membership and age estimates for Sco-Cen subgroups, highlighting discrepancies between different age determination techniques.

Findings

Sco-Cen stars are younger (~10 Myr) than β Pictoris group (~12 Myr).

Previous age estimates based on different methods may be inconsistent.

Spectroscopic lithium measurements can refine age estimates of young stellar groups.

Abstract

We have spectroscopically identified about 100 G-, K- and M-type members of the Scorpius Centaurus complex. To deduce the age of these young stars we compare their Li $\lambda$6708 absorption line strengths against those of stars in the TW Hydrae association and $\beta$ Pictoris moving group. These line strengths indicate that Sco-Cen stars are younger than $\beta$ Pic stars whose ages of ~12 Myr have previously been derived from a kinematic traceback analysis. Our derived age,~10Myr, for stars in the LCC and UCL subgroups of ScoCen is younger than previously published ages based on the moving cluster method and upper main sequence fitting. The discrepant ages are likely due to an incorrect (or lack of) cross-calibration between model-dependent and model-independent age-dating methods.