The BSN Application-I: Photometric Light Curve Solutions of Contact Binary Systems

TL;DR

This paper introduces the BSN application, a tool for faster and more efficient light curve analysis of contact binary systems using MCMC, with new features and first analyses of TESS data.

Contribution

The BSN application significantly accelerates light curve fitting and provides an improved, user-friendly interface for analyzing contact binary systems, including first TESS data analyses.

Findings

BSN is over 40 times faster than PHOEBE in synthetic light curve generation.

First light curve analyses of four contact binary systems using TESS data with BSN.

Two systems showed asymmetries modeled by starspots, with classifications as A- or W-subtype.

Abstract

Light curve analysis of W UMa-type contact binary systems using MCMC or MC methods can be time-consuming, primarily because the repeated generation of synthetic light curves tends to be relatively slow during the fitting process. Although various approaches have been proposed to address this issue, their implementation is often challenging due to complexity or uncertain performance. In this study, we introduce the BSN application, whose name is taken from the BSN project. The application is designed for analyzing contact binary system light curves, supporting photometric data, and employing an MCMC algorithm for efficient parameter estimation. The BSN application generates synthetic light curves more than 40 times faster than PHOEBE during the MCMC fitting process. The BSN application enhances light curve analysis with an expanded feature set and a more intuitive interface while maintaining compliance with established scientific standards. In addition, we present the first light curve analyses of four contact binary systems based on the TESS data, utilizing the BSN application version 1.0. We also conducted a light curve analysis using the PHOEBE Python code and compared the resulting outputs. Two of the target systems exhibited asymmetries in the maxima of their light curves, which were appropriately modeled by introducing a cold starspot on one of the components. The estimated mass ratios of these total-eclipse systems place them within the category of low mass ratio contact binary stars. The estimation of the absolute parameters for the selected systems was carried out using the $P-a$ empirical relationship. Based on the effective temperatures and masses of the components, three of the target systems were classified as A-subtype, while TIC 434222993 was identified as a W-subtype system.