Complexity in small-scale dwarf spheroidal galaxies
  Our knowledge about the dynamics, the chemical abundances and the
evolutionary histories of the more luminous dwarf spheroidal (dSph) galaxies is
constantly growing. However, very little is known about the enrichment of the
ultra-faint systems recently discovered in large numbers in large sky surveys.
Current low-resolution spectroscopy and photometric data indicate that these
galaxies are highly dark matter dominated and predominantly metal poor. On the
other hand, recent high-resolution abundance analyses indicate that some dwarf
galaxies experienced highly inhomogenous chemical enrichment, where star
formation proceeds locally on small scales. In this article, I will review the
kinematic and chemical abundance information of the Milky Way satellite dSphs
that is presently available from low- and high resolution spectroscopy.
Moreover, some of the most peculiar element and inhomogeneous enrichment
patterns will be discussed and related to the question of to what extent the
faintest dSph candidates could have contributed to the Galactic halo, compared
to more luminous systems.
