31 October 2018

Alexander Binks

Developing a Homogeneous Method to Calculate Lithium Depletion Boundary Ages in Young(-ish) Stellar Associations

Measuring ages using the lithium depletion boundary (LDB)technique can be an extremely precise and potentially accurate chronometer in stellar associations between 20 and 200 Myr given the relative model insensitivity compared to alternative age-dating methods. As lithium is burned extremely rapidly in low-mass (M-type), fully-convective stars, the observational method is simply to locate a gap in a colour-magnitude diagram (CMD) between lithium-undepleted stars and those at slightly higher masses that have undergone full depletion. To date there are approximately a dozen LDB ages reported in open clusters and moving groups.

The reported ages have, however, been measured using various calibrations, photometric bands and empirical corrections, leading to an inhomogeneous LDB age-ladder. In this talk I provide a brief introduction and critical analysis of the LDB technique, frame the current state-of-affairs amongst current LDB age estimates and provide a framework for a potentially robust, homogeneous LDB age scale, focusing (for now) solely on the Beta Pictoris moving group. I will conclude by presenting preliminary work on developing a CMD and lithium depletion model to be used a prior model in a Bayesian framework.