a) Position of the target star in the HR diagram compared with evolutionary tracks and isochrones of solar metallicity. Tracks are shown in dotted (pre-MS) and solid (main sequence onwards) colored lines; isochrones at 2 Myr and 4.6 Gyr are plotted as short-dashed and long-dashed black lines, respectively. b) ⁶Li/⁷Li ratio as a function of age for the same models showing that ⁶Li is completely destroyed within approximately the first two million years of pre-MS evolution.