Poster abstract details
PNe as observational constraints in chemical evolution models for NGC6822
Abstract
We present chemical evolution models for the dwarf irregular galaxy NGC~6822 using chemical abundances of Planetary Nebulae (PNe) and ion{H}{ii} regions as observational constraints, past an present component of the ISM respectively. Two sets of chemical abundances, one derived from collisionally excited lines (CELs) and one, from recombination lines (RLs), are used. We try to use our models as a tool to discriminate between both procedures for abundance determinations. We also discuss the predicted $Delta Y/Delta O$ values for NGC~6822.
In our chemical evolution code, the chemical contribution of low and
intermediate mass stars is time delayed, while for the massive stars
the chemical contribution follows the instantaneous recycling approximation. Our models have two main free parameters: the upper mass limit, $M_{up}$, of the initial mass function (IMF) and the mass of a well-mixed outflow. In order to reproduce the gaseous mass and O/H abundance of our observational constraints (PNe and ion{H}{ii} regions) we need to vary $M_{up}$ and the outflow rate. Some models will be present in this work.
In our chemical evolution code, the chemical contribution of low and
intermediate mass stars is time delayed, while for the massive stars
the chemical contribution follows the instantaneous recycling approximation. Our models have two main free parameters: the upper mass limit, $M_{up}$, of the initial mass function (IMF) and the mass of a well-mixed outflow. In order to reproduce the gaseous mass and O/H abundance of our observational constraints (PNe and ion{H}{ii} regions) we need to vary $M_{up}$ and the outflow rate. Some models will be present in this work.