Dynamical age of the Tucana-Horologium young stellar association

The Tucana-Horologium association is one of the closest young stellar groups to the Sun and despite the close proximity its age is still debated in the literature. We take advantage of the state-of-the-art astrometry delivered by the third data release of the Gaia space mission combined with precise radial velocity measurements obtained from high-resolution spectroscopy to investigate the dynamical age of the association. We perform an e xtensiv e traceback analysis using a combination of different samples of cluster members, metrics to e v aluate the minimum size of the association in the past and models for the galactic potential to integrate the stellar orbits back in time. The dynamical age of 38.5(-8.0)(+1.6) Myr that we derive in this paper is consistent with the various age estimates obtained from isochrone fitting in the literature (30-50 Myr) and reconciles, for the first time, the dynamical age of the Tucana-Horologium association with the age obtained from lithium depletion ( similar to 40 Myr). Our results are independent from stellar models and represent one more step towards constructing a self-consistent age scale for the young stellar groups of the Solar neighbourhood based on the 3D space motion of the stars.

Automated summary

In this study, we use the latest astronomical measurement techniques from the third data release of the Gaia space mission and precise radial velocity measurements obtained from high-resolution spectroscopy to investigate the dynamical age of the Tucana-Horologium association. By performing an extensive traceback analysis using different samples of cluster members, metrics to evaluate the association's minimum size in the past, and models for the galactic potential, we derived a dynamical age of 38.5(-8.0)(+1.6) Myr, consistent with previous age estimates obtained from isochrone fitting and lithium depletion.