Physical parameters of three field RR Lyrae stars

TL;DR

This study uses Strömgren photometry to determine physical parameters of three RR Lyrae stars, analyzing their metallicity, temperature, gravity, and pulsation stability, and addressing their classification and reddening.

Contribution

It provides a detailed comparison of three methods for estimating stellar parameters of RR Lyrae stars using photometric data.

Findings

Consistent metallicity estimates from different methods.

Identification of SS Psc as an RRc or HADS star.

Reddening values derived from multiple approaches.

Abstract

Str\"omgren $uvby-\beta$ photometry of the stars classified as RR Lyrae stars RU Piscium, SS Piscium and TU Ursae Majoris has been used to estimate their iron abundance, temperature, gravity and absolute magnitude. The stability of the pulsating period is discussed. The nature of SS Psc as a RRc or a HADS is addressed. The reddening of each star is estimated from the Str\"omgren colour indices and reddening sky maps. The results of three approaches to the determination of [Fe/H], $T_{\rm eff}$ and $\log(g)$ are discussed: Fourier light curve decomposition, the Preston $\Delta S$ index and the theoretical grids on the $(b-y)_o - c_1{_o}$ plane.