HD172189: another step in furnishing one of the best laboratories known for asteroseismic studies

TL;DR

This study provides detailed spectroscopic analysis of the binary system HD172189, enhancing its role as a laboratory for asteroseismic research by determining key stellar parameters and chemical compositions.

Contribution

First spectroscopic analysis of HD172189, combining multiple techniques to derive stellar parameters and chemical abundances, advancing its use in asteroseismic studies.

Findings

Component masses of 1.8 and 1.7 solar masses

Effective temperatures of 7600 K and 8100 K

Abundance analysis shows [Fe/H] = -0.28

Abstract

HD172189 is a spectroscopic eclipsing binary system with a rapidly-rotating pulsating delta Scuti component. It is also a member of the open cluster IC4756. These combined characteristics make it an excellent laboratory for asteroseismic studies. To date, HD172189 has been analysed in detail photometrically but not spectroscopically. For this reason we have compiled a set of spectroscopic data to determine the absolute and atmospheric parameters of the components. We determined the radial velocities (RV) of both components using four different techniques. We disentangled the binary spectra using KOREL, and performed the first abundance analysis on both disentangled spectra. By combining the spectroscopic results and the photometric data, we obtained the component masses, 1.8 and 1.7 solar masses, and radii, 4.0 and 2.4 solar radii, for inclination i = 73.2 degrees, eccentricity e = 0.28, and orbital period 5.70198 days. Effective temperatures of 7600 K and 8100 K were also determined. The measured vsini are 78 and 74 km/s, respectively, giving rotational periods of 2.50 and 1.55 days for the components. The abundance analysis shows [Fe/H] = -0.28 for the primary (pulsating) star, consistent with observations of IC4756. We also present an assessment of the different analysis techniques used to obtain the RVs and the global parameters.