Location of the CoRoT long-period variables in a two-colour diagram. Filled circles mark LPVs from LRc02, while objects from the other three runs investigated are shown as open boxes. The solid line indicates the dereddened location of M-giants according to Worthey & Lee (2011). The astrisks represent the sample of local LPVs given by Mendoza (1967). The small crosses mark the location of hydrostatic C-stars from the models by Aringer et al. (2009). The arrow indicates the direction of the interstellar reddening.