Probability density map for the R−z and x−y projections of a an ensemble of 100 000 orbits for UKS 1 in the reference frame where the bar is at rest. Simulations for three different value of the bar patterns speed (Ω_bar) are shown. The white dotted circle indicates the assumed bulge radius of ∼3 kpc according to Barbuy et al. (2018); the thick white line shows the length (∼3.4 kpc) of the physical boxy/peanut bar structure employed in the GravPot16 model. The white star and square symbols indicate the initial and end position of the cluster after a 2 Gyr backwards integration time. The black lines show the orbit of UKS 1 by assuming the central values of the observables, while the yellow colour map show the more probable regions of the space crossed by the cluster (considering the uncertainty in the observables). The orbit results are presented by adopting two different heliocentric estimates, i.e. 7.8 kpc (left panels) and 15.9 kpc (right panels). The white “star” and square symbols indicate the present and final position of the orbit of the cluster, respectively.