Differential abundance analysis of Procyon and theta Sculptoris: Comparison with abundance patterns of solar-like pairs

摘要

The precision differential abundance (PDA) technique is applied to the mid-F stars Procyon and theta Scl using spectra from the ESO UVESPOP library. We relate PDA patterns to endogenous processes related to condensation or to exogenous processes connected to Galactic chemical evolution. We employ one-dimensional LTE models, but emphasize the use of weaker lines (<= 20 m angstrom) that are typically used in such studies. We compare our results with PDAs of solar-type stars. Abundances and PDAs are determined for 28 elements: C, N, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Ba, La, Ce, Nd, Sm, Eu, and Gd. A plot of PDAs (theta Scl minus Procyon) versus Z shows a highly significant correlation. Moreover, local substructure of the plot for the elements Ca-Zn and neutron-addition elements is similar to that which can be found for solar twins. Our PDA versus Z plot structural shows similarity to plots that can be made from the extensive work of Bedell et al. (2018). That PDA structure and substructure is clearly a function of age.