[α/Fe] versus [Fe/H]. Panel a: distribution of abundances of [Ti/Fe] versus [Fe/H] of stars in Table 1. Symbols indicate the star’s class: DDP (squares), DD (triangles), CP (circles). The black line separates the stars as belonging to the thin (below) or thick (above) disks following the definition presented by Bensby et al. (2014). Colors show stars that fulfil both the chemistry-based and the kinematic criteria to belong to the thin (red) and/or the thick (blue) disk populations (see Sects. 2.1 and 2.3). In yellow we show the stars that are in a “transitory stage” between the two disk populations according to its kinematics. Stars surrounded by a red circle indicate they belong to the HAHM population, as defined by Adibekyan et al. (2012). Finally, the size of the symbols qualitatively indicate the stellar ages, being the smallest the youngest. Panel b: same details as in panel a but considering the average between [O/Fe], [Si/Fe], and [Mg/Fe] as a function of [Fe/H]. The grey dashed line shows the limit between the thin- and thick-disk stars in the [a/Fe] versus [Fe/H] space.