Contribution of proton capture reactions to the abundances of phosphorus and sulfur in FGK stars

Abstract

Elemental abundance pattern is one of the key components which gives clues for understanding not only the cluster formation, but also the chemical evolution. But the origin of the abundance pattern is yet to be completely perceived. In this study, we carried out the impact of proton-capture reaction cycles on the abundances of phosphorus (P) and sulfur (S) considering nuclear burning cycles of PCl in stars of temperature range of $0.1\times 10^{9}$–$<0.7\times 10^{9}$ K and density of $10^{2}$ g cc$^{-1}$. Such kind of temperature density situations are going to be dominant within the H-burning shell of evolved stars. We have estimated abundances of P and S in 22 FGK dwarfs and giants that span $-0.55<[\mathrm{Fe/H}]<0.2$. We observe an excellent agreement of [P/Fe] and [S/Fe] between the estimated and observed abundance values with a correlation coefficient >0.7 and >0.8, respectively, for all 22 FGK stars. Possible sources of these discrepancies are also discussed.