Date: 10.11.2026

Ganesh Pawar (CAMK PAN,TOR)

Detached Eclipsing Binary Stars as Benchmark Stars

Abstract:
Detached eclipsing binaries provide the most precise, model-independent measurements of stellar masses and radii available, which is why they serve as fundamental benchmarks for stellar models and for missions like ESA’s PLATO. With space-based photometry from TESS, these measurements are routinely quoted with sub-percent precision; but to serve as benchmarks, the derived parameters need to be stable and reliable over time, not just formally precise. By analysing TESS sectors independently, I will show that starspots, eclipse-timing variations, and third-light contamination introduce parameter shifts well above the formal errors, effects that single-epoch analyses can hide and that quietly undermine the benchmark status of these systems. Using spectral disentangling of multi-epoch, high-resolution spectra, we separate the individual spectra of each component, allowing their atmospheric parameters to be determined independently. I will also discuss why reconciling these spectroscopic effective temperatures with photometric ones is essential before we can reliably derive metallicities and ages. Finally, I will introduce MAESTRO, a new Las Cumbres Observatory Key Project that will extend this multi-epoch, multi-band approach to an all-sky sample, delivering a validated catalogue of benchmark stars.