Grid of atmospheric parameters as a function of the two generic indices CaT* and PaT, which measure the strength of Ca ii and Paschen lines, respectively. We show the positions on the grid of the three spectroscopic targets observed with the GTC, which show absorption in the Ca ii triplet. From left to right, solid lines indicate temperatures at the range 4800−7000 K with a step of 200 K. Dotted lines correspond to log  g values of 0 to 5, with a step of 1 dex, as CaT* decreases.