Galactic longitude versus distance (Bailer-Jones et al. 2021) of λ Ori cluster members (black) with members that traceback to within the core radius (CA < r_c) in red, members that traceback to the core radius within 1σ (CA − σ < r_c) in yellow, members that traceback to the core radius within 2σ (CA − 2σ < r_c) in green, and the position of the cluster centre denoted with a blue cross. Cluster members consistent with traceback to the core radius that match with the Gaia DR3 varYSO catalogue (Marton et al. 2023) are plotted with X’s.