A Chemical Evolution Model for the Fornax Dwarf Spheroidal Galaxy
  Fornax is the brightest Milky Way (MW) dwarf spheroidal galaxy and its star
formation history (SFH) has been derived from observations. We estimate the
time evolution of its gas mass and net inflow and outflow rates from the SFH
using a simple star formation law that relates the star formation rate to the
gas mass. We present a chemical evolution model on a 2D mass grid with
supernovae (SNe) as sources of metal enrichment. We find that a key parameter
controlling the enrichment is the mass M_x of the gas to mix with the ejecta
from each SN. The choice of M_x depends on the evolution of SN remnants and on
the global gas dynamics. It differs between the two types of SNe involved and
between the periods before and after Fornax became an MW satellite at time t =
t_sat . Our results indicate that due to the global gas outflow at t > t_sat ,
part of the ejecta from each SN may directly escape from Fornax. Sample results
from our model are presented and compared with data.
