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We perform the non-local thermodynamic equilibrium (NLTE) calculations for CaI-II with the updated model atom that includes new quantum-mechanical ratecoefficients for Ca I + H I collisions from two recent studies, that is, byBarklem and by Mitrushchenkov, Guitou, Belyaev, Yakovleva, Spielfiedel, andFeautrier, and investigate the accuracy of calcium abundance determinationsusing the Sun, Procyon, and five metal-poor (MP) stars with well-determinedstellar parameters. We show that both collisional recipes lead to very similarNLTE results. When using the subordinate lines of Ca I and the high-excitationlines of Ca II, NLTE provides the smaller line-to-line scatter compared withthe LTE case for each star. For Procyon, NLTE removes a steep trend with linestrength among strong Ca I lines seen in LTE and leads to consistent [Ca/H]abundances from the two ionisation stages. In the MP stars, the NLTE abundancefrom Ca II 8498 A agrees well with that from the Ca I subordinate lines. NLTElargely removes abundance discrepancies between the high-excitation lines of CaI and Ca II 8498 A obtained for our four [Fe/H] < -2 stars under the LTEassumption. We investigate the formation of the Ca I resonance line in the[Fe/H] < -2 stars. Consistent NLTE abundances from the Ca I resonance line andthe Ca II lines are found for two hyper metal-poor stars HE0107-5240 andHE1327-2326. We provide the NLTE abundance corrections for 28 lines of Ca I ina grid of model atmospheres suitable for abundance analysis of FGK-type dwarfsand subgiants.

Influence of inelastic collisions with hydrogen atoms on the non-LTE modelling of Ca I and Ca II lines in late-type stars