Precision constraints on stellar physics from main sequence detached eclipsing binaries

Abstract

We present a Bayesian framework to constrain {mass ($M$), metallicity ($Z$), stellar age ($\tau$), and the convective mixing length parameter ($\alpha_{\rm MLT}$)} in main-sequence (MS) detached eclipsing binaries (DEBs). These systems provide precise values of stellar mass and radius, offering stringent tests of stellar evolution models. We combine these with broadband magnitudes in the $B$ and $V$ bands and Gaussian priors on spectroscopic mass and metallicity, and perform Markov Chain Monte Carlo inference using a fast machine-learning surrogate for one-dimensional stellar evolution models computed with Modules for Experiments in Stellar Astrophysics. To make this approach computationally feasible, we implement an active learning strategy that adaptively selects new stellar models to evaluate, concentrating training data in regions of parameter space where the surrogate is most uncertain. Applying this framework to 38 stars in DEB systems, we recover ages more precise than previous isochrone-based determinations and obtain bounds on $\alpha_{\rm MLT}$ for a subset of lower-mass stars ($M \lesssim 1.5 M_\odot$), where convective envelopes provide sensitivity to the mixing length parameter. For several stars, the inferred $\alpha_{\rm MLT}$ values lie below the Solar-calibrated value, supporting previous indications that a universal mixing length parameter may not adequately describe convection across the main sequence. The active learning methods developed here provide a scalable route to Bayesian inference with stellar evolution models, with clear applications to additional stellar physics parameters and other precisely characterized stellar systems.