Galactic-Field Metal-Rich RR Lyrae Variables: Features of Kinematics and Abundances of Selected Chemical Elements

Abstract

We present an analysis of the relative abundance features of a number of chemical elements in the atmospheres of metal-rich (\({\textrm{[Fe/H]}}>-1\)) Galactic-field RR Lyrae variable stars and the kinematic characteristics of these stars. We have previously shown that the relative abundances of some \(\alpha\) elements: magnesium, silicon, calcium, and to a greater extent of titanium, as well as yttrium and scandium in such stars are lower than in most other types of stars bearing similar metallicity. It is found here that some of these metal-rich RR Lyrae stars also have very low relative abundances of sodium, aluminum, and nickel. The orbital parameters of all the metal-rich RR Lyrae variables studied in this paper are typical of the Galactic thin or thick disk objects, however, the unusual chemical composition let us to suggest a possible extragalactic origin for some of them.