Centaur 2013 VZ(70): Debris from Saturn's irregular moon population?

Context. Saturn has an excess of irregular moons. This is thought to be the result of past collisional events. Debris produced during such episodes in the neighborhood of a host planet can evolve into co-orbitals trapped in quasi-satellite and/or horseshoe resonant states. A recently announced centaur, 2013 VZ(70), follows an orbit that could be compatible with those of prograde Saturn's co-orbitals. Aims. We perform an exploration of the short-term dynamical evolution of 2013 VZ(70) to confirm or reject a co-orbital relationship with Saturn. A possible connection with Saturn's irregular moon population is also investigated. Methods. We studied the evolution of 2013 VZ(70) backward and forward in time using N-body simulations, factoring uncertainties into the calculations. We computed the distribution of mutual nodal distances between this centaur and a sample of moons. Results. We confirm that 2013 VZ(70) is currently trapped in a horseshoe resonant state with respect to Saturn but that it is a transient co-orbital. We also find that 2013 VZ(70) may become a quasi-satellite of Saturn in the future and that it may experience brief periods of capture as a temporary irregular moon. This centaur might also pass relatively close to known irregular moons of Saturn. Conclusions. Although an origin in trans-Neptunian space is possible, the hostile resonant environment characteristic of Saturn's neighborhood favors a scenario of in situ formation via impact, fragmentation, or tidal disruption as 2013 VZ(70) can experience encounters with Saturn at very low relative velocity. An analysis of its orbit within the context of those of the moons of Saturn suggests that 2013 VZ(70) could be related to the Inuit group, particularly Siarnaq, the largest and fastest rotating member of the group. Also, the mutual nodal distances of 2013 VZ(70) and the moons Fornjot and Thrymr are below the first percentile of the distribution.