Distances for the RR Lyrae stars UU Ceti, UW Gruis, & W Tucanae

TL;DR

This study combines ground-based and space telescope data to validate distance measurements of three RR Lyrae stars, confirming the reliability of period-luminosity relations and deriving metallicities consistent with existing literature.

Contribution

It introduces a method to estimate metallicity from TESS Fourier decompositions and validates PL-based distances against Gaia data for RR Lyrae stars.

Findings

PL distances agree with Gaia DR3 measurements

Fourier decomposition yields metallicities consistent with literature

Empirical relation between Fourier terms and pulsation period established

Abstract

B, V, i, and z bandpass observations were collected in late 2020 for three RRab type stars: UU Ceti, UW Gruis, and W Tucanae. The period-luminosity (PL) relationships of Catalen et al. (2004) and Caceres \& Catelan (2008) were applied to derive distances. These were found to be in reasonable agreement with the Gaia Early DR3 distances, lending confidence to use of the PL relationships. Fourier decompositions were applied to data from the TESS space telescope to derive, using stepwise linear regression, an empirical relationship between terms of the decomposition and the pulsation period with metallicity [Fe/H]. TESS data were available for UU Cet and W Tuc out of the three studied studies. The derived equation gave metallicities in line with the literature for both stars, lending confidence to their usage in the PL-derived distances.