  We investigate the dynamical evolution of trans-Neptunian objects (TNOs) in
typical scattered disk orbits (scattered TNOs) by performing simulations using
several thousand particles lying initially on Neptune-encountering orbits. We
explore the role of resonance sticking in the scattered disk, a phenomenon
characterized by multiple temporary resonance captures ('resonances' refers to
external mean motion resonances with Neptune, which can be described in the
form r:s, where the arguments r and s are integers). First, all scattered TNOs
evolve through intermittent temporary resonance capture events and
gravitational scattering by Neptune. Each scattered TNO experiences tens to
hundreds of resonance captures over a period of 4 Gyr, which represents about
38% of the object's lifetime (mean value). Second, resonance sticking plays an
important role at semimajor axes a < 250 AU, where the great majority of such
captures occurred. It is noteworthy that the stickiest (i.e., dominant)
resonances in the scattered disk are located within this distance range and are
those possessing the lowest argument s. This was evinced by r:1, r:2 and r:3
resonances, which played the greatest role during resonance sticking evolution,
often leading to captures in several of their neighboring resonances. Finally,
the timescales and likelihood of temporary resonance captures are roughly
proportional to resonance strength. The dominance of low s resonances is also
related to the latter. In sum, resonance sticking has an important impact on
the evolution of scattered TNOs, contributing significantly to the longevity of
these objects.
