Orbital Period Changes in IO Cep, IM Cep and TX Ari: Path to Masses of Distant Components

TL;DR

This study analyzes orbital period variations in three Algol-type binaries using combined ground and TESS data to estimate system parameters and distant component masses without spectra, aiding faint system studies.

Contribution

It introduces a method to determine binary mass ratios and distant component masses using photometric data and system geometry, bypassing the need for spectra.

Findings

Estimated masses of distant components with 10-20% uncertainty.

Determined binary system parameters from combined photometric data.

Validated a spectrally-independent approach for faint systems.

Abstract

Three Algol-type binary systems (IO Cep, IM Cep and TX Ari) showing cyclic orbital period changes are studied. The combination of time of minimum data from the ground-based observations together with high precision photometric data from the TESS satellite enabled us to estimate the basic light curve elements of binary systems and mass functions for distant components around the systems. The relation of mass ratio to the system geometry in semi-detached binary stars allowed us to determine the mass ratio of the binary components without using spectra. By using the color and distance information from the GAIA EDR3 and light contributions of the components from the light curve analysis, the astrophysical parameters of the binary components as well as the minimum masses of the distant components are obtained with an uncertainty of ~10-20 per cent indicating that the method can be a good guide for those studying with faint systems where spectra with sufficient resolution and S/N ratio are difficult to acquire.