Evidence for an interstellar dust filament in the outer heliosheath
  A recently discovered filament of polarized starlight that traces a coherent
magnetic field is shown to have several properties that are consistent with an
origin in the outer heliosheath of the heliosphere: (1) The magnetic field that
provides the best fit to the polarization position angles is directed within
6.7+-11 degrees of the observed upwind direction of the flow of interstellar
neutral helium gas through the heliosphere. (2) The magnetic field is ordered;
the component of the variation of the polarization position angles that can be
attributed to magnetic turbulence is small. (3) The axis of the elongated
filament can be approximated by a line that defines an angle of 80+/-14 degrees
with the plane that is formed by the interstellar magnetic field vector and the
vector of the inflowing neutral gas (the "BV" plane). We propose that this
polarization feature arises from aligned interstellar dust grains in the outer
heliosheath where the interstellar plasma and magnetic field are deflected
around the heliosphere. The proposed outer heliosheath location of the
polarizing grains requires confirmation by modeling grain-propagation through
three-dimensional MHD heliosphere models that simultaneously calculate torques
on asymmetric dust grains interacting with the heliosphere.
