Low-resolution spectroscopy of RR Lyrae stars in the HIC

DOI: 
Publication date: 
01/01/1997
Main author: 
Martinez-Delgado D.
IAA authors: 
Alfaro, E.J.
Authors: 
Martinez-Delgado D., Alfaro E.J.
Journal: 
European Space Agency, (Special Publication) ESA SP
Publication type: 
Article
Volume: 
Pages: 
453-455
Number: 
Abstract: 
Low-resolution spectra of 30 RR Lyrae stars contained in the Hipparcos Input Catalogue have been obtained. The targets were selected from among those for which no measurements were available, or only poor ones, of metallicity and radial velocities in the updated catalogues (Suntzeff et al. 1994; Layden 1994). Metallicities have been obtained according to two different methods; Preston's classic ΔS method and the Freeman & Rodgers (1975) method as adapted by Layden (1994). Based on recent high-resolution spectra and ΔS data compiled from the literature, we have estimated the [Fe/H] versus ΔS relationship. While a slope of -0.20 seems to be the best value fitting our data, in good agreement with recent results, the zero-point of our calibration (0.11) is slightly higher than previous ones. This value brings the Layden metal abundance scale into agreement with those metallicities derived by Suntzeff et al., following the classic ΔS method. Otherwise the globular cluster and RR Lyrae metallicities turn out to be within the same scale when this zero-point value is used.
Database: 
SCOPUS
Keywords: 
ΔS method; Metal abundance; RR Lyrae stars