An interstellar origin for high-inclination Centaurs
  We investigate the possible origins of real high-inclination Centaurs and
trans-neptunian objects using a high-resolution statistical search for stable
orbits that simulates their evolution back in time to the epoch when planet
formation ended 4.5 billion years in the past. The simulation is a precise
orbit determination method that does not involve ad hoc initial conditions or
assumptions such as those found in planetesimal disk relaxation models upon
which their conclusions depend. It can therefore be used to independently test
origin theories based on relaxation models by examining the past orbits of
specific real objects. Here, we examined 17 multiple-opposition
high-inclination Centaurs and the two polar trans-neptunian objects 2008 KV42
and (471325) 2011 KT19. The statistical distributions show that their orbits
were nearly polar 4.5 Gyr in the past, and were located in the scattered disk
and inner Oort cloud regions. Early polar inclinations cannot be accounted for
by current Solar system formation theory as the early planetesimal system must
have been nearly flat in order to explain the low-inclination asteroid and
Kuiper belts. Furthermore, the early scattered disk and inner Oort cloud
regions are believed to have been devoid of Solar system material as the
planetesimal disk could not have extended far beyond Neptune's current orbit in
order to halt the planet's outward migration. The nearly polar orbits of
high-inclination Centaurs 4.5 Gyr in the past therefore indicate their probable
early capture from the interstellar medium.
