Eclipsing binary systems with $\beta$ Cephei components. V1216 Sco

TL;DR

This paper analyzes the eclipsing binary V1216 Sco with a $eta$ Cephei pulsator, using TESS and SALT data to determine its properties, pulsations, and evolutionary history, revealing recent mass transfer and binary interaction effects.

Contribution

It provides a detailed observational and theoretical study of V1216 Sco, highlighting the role of mass transfer in its evolution, which is a novel case study for such systems.

Findings

Detected five $eta$ Cephei pulsation frequencies.

Primary star mass is 11.72 M$_{igodot}$, secondary is 4.34 M$_{igodot}$.

Secondary is near Roche lobe, indicating recent mass transfer.

Abstract

We present a detailed analysis of the high-mass binary system V1216 Sco, an eclipsing Algol-type binary hosting a $\beta$ Cephei pulsator, with an orbital period of 3.92 days. This system was analyzed using TESS photometry and high-resolution spectroscopy from SALT HRS to investigate its orbital parameters, stellar properties, and evolutionary history. The TESS light curve, comprising over 12000 data points, revealed five independent pulsation frequencies within the beta Cephei range of 5 to 7 d$^{-1}$. Spectroscopic analysis provided radial velocities and disentangled atmospheric parameters, enabling precise orbital and evolutionary modeling. The system features a primary star of 11.72 M$_{\odot}$ and a secondary of 4.34 M$_{\odot}$. The secondary star has a radius near its Roche lobe, indicating recent or ongoing mass transfer. Evolutionary modeling with MESA-binary suggests that V1216 Sco underwent a case A mass transfer scenario, where mass transfer began while the donor was still on the main sequence. The system's evolutionary models indicate an age of 15 to 30 million years, highlighting the significant impact of binary interactions on stellar evolution. This study underscores the value of combining observational and theoretical approaches to understanding complex systems like V1216 Sco, emphasizing the role of mass transfer in shaping binary star evolution.