Tests and calibrations of stellar models with two triply eclipsing triple systems

¹ Dipartimento di Fisica “Enrico Fermi”, Università di Pisa, Largo Pontecorvo 3, I-56127 Pisa, Italy
² INFN, Sezione di Pisa, Largo Pontecorvo 3, I-56127 Pisa, Italy

^⋆ Corresponding author; valle@df.unipi.it

Received: 4 October 2024
Accepted: 4 February 2025

Abstract

Aims. We investigated the possibility of using two recently characterised triply eclipsing triple systems to constrain stellar model parameters. We specifically focused on evaluating the influence of the underlying astrophysical assumptions employed in the characterisation of the system to fix absolute values of the radii, effective temperatures, and metallicity.

Methods. We used dense grids of pre-computed stellar models to fit the data for the triply eclipsing systems with a modified version of the SCEPtER pipeline

Results. We achieve an excellent agreement with observational data for TIC 650024463, which comprises three low-mass main-sequence (MS) stars. We find it has an age of 9.0^+1.4_-1.1 Gyr and a multimodal posterior density. Characterising TIC 323486857 proved more challenging. This system comprises two intermediate-mass MS stars and a slightly more massive tertiary in the red giant branch phase. For this last system we tested alternative scenarios for convective core overshooting. When all stars were assumed to have the same overshooting efficiency, significant discrepancies arose with the observed data for the tertiary star. This discrepancy may arise from the different assumptions regarding overshooting efficiency made for the observational characterisation of the system, in which an increasing overshooting efficiency with stellar mass was adopted. By allowing independent overshooting efficiencies for all stars, we recovered a solution close to that adopted in the system observational characterisation. Encouragingly, despite the relevant differences between the adopted stellar models and those used for the observational characterisation, we found a system age of 2.33^+0.18_-0.16 Gyr in all the tested scenarios, and this age is in agreement with independent determinations.