GALAH DR3 RR Lyrae abundances

Notably, we discovered a metal-rich tail, with [Fe/H] values ranging from ~1 to approximately solar metallicity. This sub-group includes almost 1/4 of the sample, it is characterized by thin disc kinematics and displays sub- solar alpha-element abundances, marginally consistent with the majority of the MW stars. Surprisingly, they differ distinctly from typical MW disc stars in terms of the s-process elements Y and Ba.

We took advantage of similar data available in the literature and built a total sample of 535 field RRLs for which we estimated kinematical and dynamical properties. We found that metal- rich RRLs (1/3 of the sample) likely represent an old component of the MW thin disc. We also detected RRLs with retrograde orbits and provided preliminary associations with the Gaia-Sausage-Enceladus, Helmi, Sequoia, Sagittarius, and Thamnos stellar streams.