Abstract

Phosphorus is a key element for life and may be produced in a variety of nucleosynthesis channels. However, phosphorus has few accessible absorption lines making abundance measurements in stars difficult. To better understand how this odd-Z element is created, my collaborators and I have conducted a study of phosphorus in the Galaxy by measuring P abundances using the Habitable-zone Planet Finder on the Hobby-Eberly telescope. We have found that phosphorus abundances are similar to the alpha elements, especially Mg. We also find a difference in [P/Fe] of ~0.1 dex between thin and thick disk stars classified with kinematics. Finally, we have preliminary [P/Fe] ratios in halo stars likely associated with the Gaia-Enceladus-Sausage system.