Toomre diagram for five HPM stars. The solid red isovelocity curves represent constant total space velocities from 50 to 500 steps of 50 km s⁻¹. The vertical gray band corresponds to a velocity of S_LSR = −230 ± 10 km s⁻¹ (L. Necib & T. Lin 2022). Stars are classified as retrograde if their velocity relative to the LSR satisfies V_LSR < −230 km s⁻¹, whereas stars with V_LSR ≥ −230 km s⁻¹ are considered prograde in the Galaxy. Background blue points represent APOGEE DR17 stars selected using quality cuts as described in the text.