We have obtained Gemini/GMOS spectra of 28 regions located across the interacting group NGC 6845 , spanning from the inner regions of the four major galaxies ( NGC 6845A , B , C , D ) to the tidal tails of NGC 6845A .
All regions in the tails are star-forming objects with ages younger than 10 Myr .
We derived the gas-phase metallicity gradients across NGC 6845A and its two tails and we find that these are shallower than those for isolated galaxies .
NGC 6845A has a gas-phase oxygen central metallicity of 12+log ( O/H ) \sim 8.5 and a flat gas-phase metallicity gradient ( \beta =0.002 \pm 0.004 dex kpc ^ { -1 } ) out to \sim 4 \times R _ { 25 } ( to the end of the longest tidal tail ) .
Considering the mass-metallicity relation , the central region of NGC 6845A displays a lower oxygen abundance than the expected for its mass .
Taking into account this fact and considering the flat oxygen distribution measured along the eastern tidal tail , we suggest that an interaction event has produced a dilution in the central metallicity of this galaxy and the observed flattening in its metal distribution .
We found that the star formation process along the eastern tidal structure has not been efficient enough to increase the oxygen abundances in this place , suggesting that this structure was formed from enriched material .