Investigation of the Puzzling Abundance Pattern in the Stars of the
  Fornax Dwarf Spheroidal Galaxy
  Many works have found unusual characteristics of elemental abundances in
nearby dwarf galaxies. This implies that there is a key factor of galactic
evolution that is different from that of the Milky Way (MW). The chemical
abundances of the stars in the Fornax dwarf spheroidal galaxy (Fornax dSph)
provide excellent information for setting constraints on the models of the
galactic chemical evolution. In this work, adopting the five-component
approach, we fit the abundances of the Fornax dSph stars, including $\alpha$
elements, iron group elements and neutron-capture elements. For most sample
stars, the relative contributions from the various processes to the elemental
abundances are not usually in the MW proportions. We find that the
contributions from massive stars to the primary $\alpha$ elements and iron
group elements increase monotonously with increasing [Fe/H]. This means that
the effect of the galactic wind is not strong enough to halt star formation and
the contributions from massive stars to $\alpha$ elements did not halted for
[Fe/H]$\lesssim$-0.5. The average contributed ratios of various processes
between the dSph stars and the MW stars monotonously decrease with increasing
progenitor mass. This is important evidence of a bottom-heavy initial mass
function (IMF) for the Fonax dSph, compared to the MW. Considering a
bottom-heavy IMF for the dSph, the observed relations of [$\alpha$/Fe] versus
[Fe/H], [iron group/Fe] versus [Fe/H] and [neutron-capture/Fe] versus [Fe/H]
for the dSph stars can be explained.
