We have begun developing a new metallicity calibration for RR Lyrae stars that includes high-temperature phase regions. Our calibration is an updated and expanded version of the Delta-S, equivalent width method, but which is applicable for most phases of the pulsation, and for the hotter, shorter-period RRc stars. This calibration will be constructed from spectral observations of well studied, bright RR Lyrae stars with metallicities from published high-resolution studies, within the range −2.5<[Fe/H]<−0.3. Phase information for our calibration stars were taken from the AAVSO website, and the MacAdam Student Observatory at the University of Kentucky. Low-resolution spectroscopy (R∼1000) was obtained using the McDonald Observatory, 2.1 meter telescope. Here we present our preliminary data, and find the phase region where the calibration will break down.
@article{arxiv.1310.0590,
title = {A New RR Lyrae Metallicity Calibration},
author = {E. Spalding and R. Wilhelm and N. De Lee},
journal= {arXiv preprint arXiv:1310.0590},
year = {2013}
}
Comments
Presented at the "40 Years of Variable Stars: A Celebration of Contributions by Horace A. Smith" conference (arXiv:1310.0149). 4 pages, 2 figures