Overview of observations of O⁶⁺ and O⁵⁺ at comet 67P during the Rosetta mission. (a) Time instances analysed in the study, represented by red lines. (b) Instances where O⁶⁺ and O⁵⁺ are observed, represented by green lines. (c) Cometocentric and heliocentric distance for the entire Rosetta mission. The solar wind cavity is symbolised by the grey area. The large cometocentric distance at the end of March 2016 is due to the nightside excursion (Behar et al. 2018).