Centaur 2013 VZ70: Debris from Saturn's irregular moon population?

Abstract

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 VZ70, 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 VZ70 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 VZ70 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 VZ70 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 VZ70 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 VZ70 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 VZ70 could be related to the Inuit group. Also, the mutual nodal distances of 2013 VZ70 and the moons Fornjot and Thrymr are below the first percentile of the distribution.

10 pages, 8 figures, 5 tables, 1 appendix. Accepted for publication in Astronomy and Astrophysics. Abstract abridged. After language edition

References in corpus (12)

• Array Programming with NumPy
• The NumPy array: a structure for efficient numerical computation
• astroquery: An Astronomical Web-Querying Package in Python
• Irregular Satellites of the Planets: Products of Capture in the Early Solar System
• Quasi-satellite orbits in the general context of dynamics in the 1:1 mean motion resonance. Perturbative treatment
• A new perspective on the irregular satellites of Saturn - I Dynamical and collisional history
• Earth's Minimoons: Opportunities for Science and Technology
• Periodic orbits of the retrograde coorbital problem
• Non-resonant secular dynamics of trans-Neptunian objects perturbed by a distant super-Earth
• A new perspective on the irregular satellites of Saturn - II Dynamical and physical origin
• Using Mars co-orbitals to estimate the importance of rotation-induced YORP break-up events in Earth co-orbital space
• The active centaur 2020 MK4