Hertzsprung-Russell diagram of all analysed stars. M_V0 is a mean V absolute magnitude corrected for extinction A_V = 0.25 mag (Paunzen et al. 2011) assuming the distance modulus m − M = 18.49 mag as given by Pietrzyński et al. (2013); (V − I)₀ is the colour index corrected for the corresponding interstellar reddening by 0.1 mag. Open circles clustering towards the main sequence indicate mCP candidates, the square denoted by 1 is the mean position of star 1 (135.3 4273), which is a short-period Cepheid. star 2 (135.30 107) is a normal non-variable K giant. Stars 12 and 14 are mCP candidates suspected for their rotationally modulated light variations.