Tentative Identification of Interstellar Dust in the Magnetic Wall of the Heliosphere

Abstract

October 8, 2018Two sets of data show that small interstellar grains captured in interstellar magnetic fields, → B IS , draped over the heliosphere appear to polarize the light of nearby stars. The polarizing grains couple to → B IS , while larger grains couple to the cloud velocity. The maximum polarization direction, P max , is offset in ecliptic longitude by ∆λ ∼ +35 o from the upwind direction, and the polarization peak is enhanced for stars near the ecliptic plane. A band of weak polarization stretches through the southern ecliptic hemisphere between the P max region and the downwind direction. The P max direction indicates that → B IS at the heliosphere is directed towards ℓ∼105 o , forming an angle of ∼75 o with the inflowing gas. Grain alignment appears stable as the grains approach the heliosphere. The disruption of grain alignment in the tenuous local interstellar material (ISM) by stochastic collisions is ∼600 times slower than in the denser clouds for which grain alignment theory has been developed, however grain alignment mechanisms are still fast, and are boosted by compression of → B IS at the heliosphere. The polarization vanishes where the outer heliosheath magnetic fields become tangled or reconnect. A similar offset seen in energetic neutral atoms may form inside of the polarization region, where the plasma is pinched by opposing magnetic fields. The composition of dust in the interstellar cloud surrounding the solar system appears to be similar to olivines, and significant quantities of carbonaceous grains can be ruled out. fringent medium where the opacity parallel to → B IS is lower than the opacity perpendicular to → B IS , resulting in a polarization maximum when the sightline is perpendicular to the magnetic field direction,k B ( §4). The location of the polarization patch coincides with most of the mass of nearby interstellar material (ISM, Frisch & York 1983), and with the upwind direction of the bulk flow of ISM past the solar location .I recently discovered that this weak polarization coincides with the heliosphere nose region, and suggested an origin associated with magnetically aligned small grains trapped in the interstellar field lines at the magnetic wall of the heliosphere (Frisch 2005, Paper I). Paper I showed that the region of maximum polarization is offset by δλ ∼ +35 o along the ecliptic plane from the large-grain inflow direction. Evidently, at the heliosphere small grains with large charge-to-mass ratios, Q/M, trace the interstellar magnetic field direction, → B IS , 1 The SF02 radiative transfer models are based on Version 90.05 of the CLOUDY code.

Uncorrelated universe: Statistical anisotropy and the vanishing angular correlation function in WMAP years 1–3

“…A number of authors have attempted to explain the observed quadrupole-octopole correlations in terms of a new foreground [51][52][53][54][55][56]. (Some of these also attempted to explain the absence of large angle correlations, for which there are also other proffered explanations [57][58][59][60][61][62][63].)…”

“…(Some of these also attempted to explain the absence of large angle correlations, for which there are also other proffered explanations [57][58][59][60][61][62][63].) Only one of the proposals ( [53]) can possibly explain the ecliptic correlations, as all the others are extragalactic. Some do claim to explain the less-significant dipole correlations.…”

Is the Sun Embedded in a Typical Interstellar Cloud?

“…The S1 subshell parameters used in the above figures correspond to a shell center at (ℓ,b)=(351 • ,−2 • ) and a distance of 78 pc away, a shell radius of 75 pc, and magnetic field angles B θ = 71 • and B φ = −42 • . The dots show stars within 50 pc with polarization data, and the red bars show polarization vectors for stars where polarizations are larger than 2.5σ [66,47,16].…”

Cosmological Implications of the CMB Large-Scale Structure

“…Nonetheless, an obvious possible cause of the anisotropy is contamination by a pernicious foreground (see, e.g., Slosar & Seljak 2004;Bielewicz et al 2005;Copi et al 2006). In this class of explanation, some workers have suggested that the observed quadrupole-octopole alignment might be due to the ReesSciama effect (Rakic et al 2006;Rakic & Schwarz 2007), interstellar dust (Frisch 2005), the presence of local voids (Inoue & Silk 2006), or even the Sunyaev-Zeldovich effect (Peiris & Smith 2010). Another proposal by Vale (2005) argues that the unexpected anisotropy might be due to a moving lens effect associated with the Great Attractor, though its influence may be too small to fully account for the observations (Cooray & Seto 2005).…”