The Infrared CaII Triplet as an Indicator of Metallicity of RR Lyrae Stars

George Wallerstein
University of Washington

ABSTRACT

The Gaia satellite will obtain spectra of resolution 10,000 from about 8400 to 8750 A of all of its target stars. We are measuring the equivalent widths of the Ca II triplet and Paschen lines on our echelle spectra at resolutions of 30,000 and 10,000 of RR Lyrae stars of known delta S to provide a metallicity calibration of the thousands of RR Lyrae stars that will be observed by Gaia.