Left: vector point diagram of proper motion distributions among all Gaia DR3 stars over the 2.5 × 2.5 deg² query area centered on Mon R2. The color bar indicates the astrometric membership probability (P _astrom) as described in the text. Middle: stars with astrometric membership probability P _astrom > 0.25. Right: field stars excluded from the candidate member sample as a result of low astrometric membership probability.