The chemical content of a sample of dwarf irregular galaxies

Abstract

We present abundances of neon, nitrogen and oxygen of some nearby dwarf irregular galaxies. The elemental abundances are retrieved from long-slit spectroscopy of H ii regions in the objects. The abundances are found to be sub-solar in all cases. For the dwarf irregular galaxy DDO 190 the abundances reported in this work are the first ever published. One object, DDO 167, proved to have an oxygen abundance about similar to the one of I Zw 18, even though the uncertainties are high. A comparison of the chemical abundances between all the groups of gas-rich galaxies have been performed and the main conclusion is that the dwarf gas-rich galaxies are not distinguishable on the basis of their chemical content.