Median 6-σ detection limits in the K_s band for F- (red), A- (green), and B-type (blue) stars, in direct imaging (plain lines) and coronagraphic (dashed lines) modes. The coronagraphic detection limits are better than the direct imaging ones from 2″ on, for the reasons given in Sect. 4.3. The measured separations ρ and magnitude differences ΔK_s of companion candidates confirmed through multi-epoch observations and those with an undefined status are indicated by filled and empty circles, respectively. The confirmed companion candidate to ι Crt, which was only observed in the H band, is marked by the red square assuming a (H−K) colour close to 0. The dash-dotted line at indicates the occulting mask radius.