Modeling of multimode radially pulsating High-Amplitude Delta Scuti stars from the OGLE Galactic bulge sample

TL;DR

This paper models high-amplitude Delta Scuti stars pulsating in multiple radial modes using OGLE data, determining their physical parameters and identifying potential SX Phoenicis candidates for asteroseismic studies.

Contribution

It introduces a grid of pulsation models for multi-mode HADS from OGLE data and derives their physical parameters, advancing understanding of their internal structure.

Findings

Determined physical parameters for 176 HADS stars.

Identified 16 candidates as SX Phoenicis stars.

Analyzed distribution of stellar properties.

Abstract

Thanks to relatively firm mode identification, possible based on period ratios only, High Amplitude Delta Scuti Stars pulsating in at least three radial modes are promising targets for asteroseismic inference. In this study we used the most numerous sample of HADS from the OGLE inner bulge fields that likely pulsate in either three or four radial modes simultaneously. We have computed a grid of pulsation models along evolutionary tracks and determined the physical parameters of stars by matching their pulsation periods and period ratios. For 176 HADS we determined physical parameters, i.e. masses, luminosities, effective temperatures, metallicities and ages. We present the distribution of physical parameters and discuss their properties. We selected 16 candidates for SX Phoenicis stars.