Fe and P abundances in 163 halo stars with HPF

To understand how P has evolved in the solar neighborhood, we measured abundances for 163 FGK stars over a range of -1.09<[Fe/H]<0.47 using observations from the Habitable-zone Planet Finder instrument on the Hobby-Eberly Telescope. Atmospheric parameters were calculated by fitting a combination of astrometry, photometry, and Fe I line equivalent widths.

Phosphorus abundances were measured by matching synthetic spectra to a P I feature at 10529.52{AA}. Our [P/Fe] ratios show that chemical evolution models generally underpredict P over the observed metallicity range. Additionally, we find that the [P/Fe] differs by ~0.1dex between thin disk and thick disk stars that were identified with kinematics.