O and Fe abundance correlations and distributions inferred for the thick and thin disk

TL;DR

This study analyzes the correlation between oxygen and iron abundances in different Galactic stellar populations, using empirical data and chemical evolution models to infer their formation and evolution histories.

Contribution

It establishes a linear [Fe/H]-[O/H] relation across stellar populations and interprets abundance distributions with multistage closed-(box+reservoir) models, revealing inflow/outflow dynamics.

Findings

Oxygen and iron abundances follow a linear correlation in different populations.

Outflow rates are lower in the thick and thin disks compared to the halo.

Iron-to-oxygen yield ratios align with supernova nucleosynthesis models.

Abstract

A linear [Fe/H]-[O/H] relation is found for different stellar populations in the Galaxy (halo, thick disk, thin disk) from a data sample obtained in a recent investigation (Ram{\'\i}rez et al. 2013). These correlations support previous results inferred from poorer samples: stars display a "main sequence" expressed as [Fe/H] = $a$[O/H$]+b\mp\Delta b$ where a unit slope, $a=1$, implies a constant [O/Fe] abundance ratio. Oxygen and iron empirical abundance distributions are then determined for different subsamples, which are well explained by the theoretical predictions of multistage closed-(box+reservoir) (MCBR) chemical evolution models by taking into account the found correlations. The interpretation of these distributions in the framework of MCBR models gives us clues about inflow/outflow rates in these different Galactic regions and their corresponding evolution. Outflow rate for the thick and the thin disks are lower than the halo outflow rate. Moreover if the thin disk built up from the thick disk, both systems result of comparable masses. Besides that, the iron-to-oxygen yield ratio and the primary to not primary contribution ratio for the iron production are obtained from the data, resulting consistent with SNII progenitor nucleosynthesis and with the iron production from SNIa supernova events.