Distributions of the measured parameters in L1251A: a) the gas volume density, n_H2; b) the NH₃ column density, N_NH3; c) the kinetic temperature, T_kin; and (d) the excitation temperature, T_ex. Three parameters n_H2, N_NH3, and T_kin were measured at the 54 positions where both the NH₃(1, 1) and (2, 2) lines were observed, whereas T_ex was estimated from the NH₃(1, 1) lines, which are not very weak. Each color box has a size of 40′′×40′′ and its bottom left corner corresponds to the telescope pointing. The contours are the NH₃(1, 1) integrated intensity map. The starting point for the contour levels is 0.2 K km s^-1; the increment is 1.0 K km s^-1. The (0, 0) map position is as in Fig. 1. We note that for the beam filling factor η< 1, certain parameters could be larger (see Sects. 3 and 3.1 for details).