HD\,139614 is known to be a ∼14-Myr-old, possibly pre-main-sequence star in the Sco-Cen OB association in the Upper Centaurus-Lupus subgroup, with a slightly warped circumstellar disc containing ring structures hinting at one or more planets. The star's chemical abundance pattern is metal-deficient except for volatile elements, which places it in the λ Boo class and suggests it has recently accreted gas-rich but dust-poor material. We identify seven dipole and four radial pulsation modes among its δ Sct pulsations using the TESS light curve and an \'echelle diagram. Precision modelling with the MESA stellar evolution and GYRE stellar oscillation programs confirms it is on the pre-main sequence. Asteroseismic, grid-based modelling suggests an age of 10.75±0.77 Myr, a mass of 1.52±0.02 M⊙, and a global metal abundance of Z=0.0100±0.0010. This represents the first asteroseismic determination of the bulk metallicity of a λ Boo star. The precise age and metallicity offer a benchmark for age estimates in Upper Centaurus--Lupus, and for understanding disc retention and planet formation around intermediate-mass stars.
@article{arxiv.2011.11821,
title = {A precise asteroseismic age and metallicity for HD 139614: a pre-main-sequence star with a protoplanetary disc in Upper-Centaurus Lupus},
author = {Simon J. Murphy and Meridith Joyce and Timothy R. Bedding and Timothy R. White and Mihkel Kama},
journal= {arXiv preprint arXiv:2011.11821},
year = {2021}
}