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

TL;DR

This study applies the precision differential abundance technique to Procyon and Theta Sculptoris, revealing abundance patterns linked to stellar and galactic processes, and compares these with solar-like stars to understand chemical evolution.

Contribution

It introduces a detailed differential abundance analysis of Procyon and Theta Sculptoris using weak spectral lines, highlighting their abundance pattern correlations with stellar age and galactic evolution.

Findings

PDA patterns correlate strongly with stellar metallicity.

Substructure in abundance differences resembles solar twins.

PDA structures are age-dependent.

Abstract

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 (GCE). We employ one-dimensional LTE models, but emphasize the use of weaker lines ($\leq$ 20 m\AA) than 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) vs. $Z$ 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 vs. $Z$ plot structural 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.