Reconstructing post-common envelope white dwarf+main sequence binary histories through inverse population synthesis techniques

TL;DR

This paper introduces an inverse population synthesis algorithm to reconstruct the evolutionary histories of white dwarf+main sequence binary systems, providing insights into their progenitors and common-envelope evolution.

Contribution

The paper presents a novel general-purpose inverse population synthesis method applied to eclipsing binaries, revealing key features of binary evolution and common-envelope parameters.

Findings

Identified a mild anticorrelation between $ m \alpha_{CE}$ and secondary mass.

Found no universal $ m \alpha_{CE}$ value, suggesting diverse evolutionary pathways.

Achieved high accuracy in reconstructing initial parameters of observed binaries.

Abstract

The evolution of binary stellar systems involves a wide range of physical processes, many of which are not yet well understood. We aim to build a general-purpose algorithm based on inverse population synthesis techniques, able to reconstruct the past history of binary systems. This algorithm will be applied to a sample of eclipsing binaries, aiming to ascertain their progenitors and past histories. Once validated, it was applied to a sample 30 white dwarf plus main-sequence eclipsing binaries observed by the Zwicky Transient Facility survey. We determined the input space parameters of the progenitors for the 30 eclipsing binary systems to which the algorithm was applied. These parameters included the initial primary and secondary masses, the orbital separation and eccentricity, the common-envelope efficiency ($\alpha_{\rm CE}$), and the age at which the system was formed. Furthermore, the analysis of the global properties revealed some important features: a mild anticorrelation between the common-envelope efficiency parameter and the secondary mass, the absence of a universal value of $\alpha_{\rm CE}$ along with no need for internal energy, although in the low-mass regime, the high values of $\alpha_{\rm CE}$ suggest a possible contribution, and an initial thermalized eccentricity distribution. Although a strong degeneracy among the input parameters exists in the reconstruction of post-common envelope binary systems, the high accuracy obtained for the eclipsing-binary systems analyzed here has allowed our algorithm to make a reasonable determination of the initial parameters without the need to include external constraints. The global properties found here so far, can be substantially improved when analyzing a future volume-complete sample.