Summary figure for UBC 103. Top two figures: colour-magnitude diagram (left) and sky coordinates of the sources (right). Bottom two figures: histograms of the parallax (left) and total proper motion (right). In all figures: blue circles or bins indicate cluster stars listed in Castro-Ginard et al. (2020), here represented by their Gaia EDR3 data; filled green circles are the observed stars; filled orange circles or bins indicate other stars found in Gaia EDR3 within 2σ from the average cluster values (see Sect. 4). Additionally, empty black circles indicate a potential separate population of stars (see Sect. 4.1); the gray dashed and dotted lines correspond to the best fitted isochrones from Padova and MIST databases, respectively, both for a value of 70 Ma and A_V = 1.6.