  The dwarf planet Pluto is known to host an extended system of five co-planar
satellites. Previous studies have explored the formation and evolution of the
system in isolation, neglecting perturbative effects by the Sun. Here we show
that secular evolution due to the Sun can strongly affect the evolution of
outer satellites and rings in the system, if such exist. Although precession
due to extended gravitational potential from the inner Pluto-Charon binary
quench such secular evolution up to $a_{crit}\sim0.0035$ AU ($\sim0.09$
$R_{Hill}$ the Hill radius; including all of the currently known satellites),
outer orbits can be significantly altered. In particular, we find that
\emph{co-planar} rings and satellites should not exist beyond $a_{crit}$;
rather, satellites and dust particles in these regions secularly evolve on
timescales ranging between $10^{4}-10^{6}$ yrs, and quasi-periodically change
their inclinations and eccentricities through secular evolution (Lidov-Kozai
oscillations). Such oscillations can lead to high inclinations and
eccentricities, constraining the range where such satellites (and dust
particles) can exist without crossing the orbits of the inner satellites, or
crossing the outer Hill stability range. Outer satellites, if such exist are
therefore likely to be \emph{irregular} satellites, with orbits limited to be
non-circular and/or highly inclined. These could be potentially detected and
probed by the New-Horizon mission, possibly providing direct evidence for the
secular evolution of the Pluto satellite system, and shedding new light on its
origins.
