Population classification of the sample of GK dwarfs. Left: Classification of thin- and thick-disc stars based on a probability ratio (TD/D) defined in Bensby et al. (2014) (here, the “in-between” stars are grouped into “thick-disc” stars). Right: The Toomre diagram of the sample of GK dwarfs based on their kinematic data (U_LSR, V_LSR, and W_LSR, relative to the local standard of rest (LSR); Bensby et al. 2014). The dashed curves indicate the isotropic total space velocities (v_tot). A subset sample of M dwarfs with available kinematic data (Ishikawa et al. 2022) are also shown for comparison.