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

TL;DR

This study uses two triply eclipsing triple star systems to test and calibrate stellar models, focusing on the effects of astrophysical assumptions like convective core overshooting on derived stellar parameters and ages.

Contribution

It demonstrates how detailed modeling of triply eclipsing systems can constrain stellar model parameters and assess the impact of different assumptions such as overshooting efficiency.

Findings

Excellent model-data agreement for TIC 650024463 with an age of ~9 Gyr.

Challenges in modeling TIC 323486857 due to overshooting assumptions.

Consistent age estimate (~2.3 Gyr) across different modeling scenarios.

Abstract

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. 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. 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.