Cumulative theoretical uncertainties in lithium depletion boundary age

Abstract

AbstractWe performed a detailed analysis of the main theoretical uncertainties affecting the age at the lithium depletion boundary (LDB). We computed almost 12 000 pre‐main sequence models with mass in the range [0.06, 0.4] M⊙ by varying input physics (nuclear reaction cross sections, outer boundary conditions, equation of state, and radiative opacity), initial chemical abundances (total metallicity, helium and deuterium abundances, and heavy element mixture), and convection efficiency (mixing length parameter, αML). As a first step, we investigated the effect of varying all these quantities individually within their extreme values. Then, we analysed the impact of simultaneously perturbing the main input physics/chemical abundances/parameters that affect the LDB age, without making any a priori assumption of independence among each other. Such an approach allowed us to build the cumulative error stripe which defines the edges of the maximum uncertainty region in the theoretical LDB age. The error stripe ranges from about 5–15 % for αML = 1.00, and it slightly reduces to about 5–10 % for a solar calibrated αML. About 40 % of the total error stripe is due to the uncertainty in the adopted initial chemical composition.