Chemical evolution of the Small Magellanic Cloud based on planetary nebulae

TL;DR

This study uses planetary nebulae data to trace the chemical evolution of the Small Magellanic Cloud, revealing an age-metallicity relation and suggesting recent star formation activity in the galaxy.

Contribution

It provides new high-quality spectral data and derives an accurate age-metallicity relation for the SMC based on planetary nebulae, improving understanding of its chemical evolution.

Findings

Derived an age-metallicity relation for the SMC.

Identified a star formation burst in the last 2-3 Gyr.

Provided improved spectral flux data for SMC PNe.

Abstract

We investigate the chemical evolution of the Small Magellanic Cloud (SMC) based on abundance data of planetary nebulae (PNe). The main goal is to investigate the time evolution of the oxygen abundance in this galaxy by deriving an age-metallicity relation. Such a relation is of fundamental importance as an observational constraint of chemical evolution models of the SMC. We have used high quality PNe data in order to derive the properties of the progenitor stars, so that the stellar ages could be estimated. We collected a large number of measured spectral fluxes for each nebula, and derived accurate physical parameters and nebular abundances. New spectral data for a sample of SMC PNe obtained between 1999 and 2002 are also presented. These data are used together with data available in the literature to improve the accuracy of the fluxes for each spectral line. We obtained accurate chemical abundances for PNe in the Small Magellanic Cloud, which can be useful as tools in the study of the chemical evolution of this galaxy and of Local Group galaxies. We present the resulting oxygen versus age diagram and a similar relation involving the [Fe/H] metallicity based on a correlation with stellar data. We discuss the implications of the derived age-metallicity relation for the SMC formation, in particular by suggesting a star formation burst in the last 2-3 Gyr.