A Photometric and Spectroscopic Study of the Short-Period Algol EW Bo\"{o}tis with a $\delta$ Sct Pulsator

TL;DR

This study combines photometry and spectroscopy to analyze the short-period Algol EW Boo, revealing detailed stellar parameters, orbital variations, and pulsation modes, contributing to understanding of binary evolution and stellar pulsations.

Contribution

It provides the first detailed analysis of EW Boo using TESS data and high-resolution spectra, including precise stellar parameters and pulsation modes, which is novel for this system.

Findings

Component masses and radii determined with over 3% precision

Detected 17 pressure-mode pulsations in the primary star

Orbital period variation shows a 17.6-year periodic oscillation

Abstract

In this paper, we present TESS photometry and high-resolution spectra of the short-period Algol EW Boo. We obtained double-lined radial velocities (RVs) from the time-series spectra and measured the effective temperature of the primary star as $T_{\rm{eff,1}}$ = 8560 $\pm$ 118 K. For the orbital period study, we collected all times of minima available for over the last 30 years. It was found that the eclipse timing variation of the system could be represented by a periodic oscillation of 17.6 $\pm$ 0.3 years with a semi-amplitude of 0.0041 $\pm$ 0.0001 d. The orbital and physical parameters were derived by simultaneously analyzing the TESS light and RV curves using the Wilson-Devinney (WD) binary star modeling code. The component masses and radii were showed over 3% precision: $M_{1}$ = 2.67 $\pm $ 0.08 M$_{\odot}$, $M_{2}$ = 0.43 $\pm $ 0.01 M$_{\odot}$, $R_{1}$ = 2.01 $\pm $ 0.02 R$_{\odot}$, and $R_{2}$ = 1.35 $\pm $ 0.01 R$_{\odot}$. Furthermore, multiple frequency analyses were performed for the light-curve residuals from the WD model. As a result, we detected 17 pressure-mode pulsations in the region of 40.15 - 52.37 d$^{-1}$. The absolute dimensions and pulsation characteristics showed that the $\delta$ Sct pulsator was the more massive and hotter primary star of the EW Boo.