Paper: astro-ph/0506293
Date: Mon, 13 Jun 2005 22:30:30 GMT (178kb)

Title: Tentative Identification of Interstellar Dust in Heliosphere Nose

Authors: Priscilla C. Frisch
Comments: Submitted to Astrophysical Journal Letters
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Observations of polarization toward nearby stars in the upwind direction made
by (Tinbergen, 1982) are consistent with an origin associated with interstellar
dust grains entrained in interstellar magnetic fields wrapped around the
heliosphere nose. The region of maximum polarization is centered around
ecliptic coordinates (295 deg,0 deg). The direction of maximum polarization is
offset along the ecliptic longitude by about 35 deg from the heliosphere nose.
An offset is also seen between the region with the best aligned dust grains
(ecliptic longitudes 281 deg to 330 deg) and inflowing interstellar dust grains
observed by Ulysses and Galileo, and in this region polarization strength
anti-correlates with ecliptic latitude. These offsets support an interpretation
whereby the maximum polarization occurs in a direction perpendicular to the
interstellar field lines, the region of consistent polarization angle shows the
deflection of small grains, and the inflow of larger grains shows the
undeflected grain population. The offsets in the aligned dust direction, and
separate upwind directions for inflowing dust, HeI, and HI, are understood if
the filtration factors for each species depend on gyroradius, so that observed
upwind directions respond to heliosheath asymmetries introduced by the draped
interstellar magnetic field. The presence of interstellar dust grains captured
in the heliosheath represents a potentially important, but weak, large scale
contamination of the cosmic microwave background signal.

\\ ( http://arXiv.org/abs/astro-ph/0506293 , 178kb)