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The distribution of interstellar dust grains (ISDG) observed in the Solar System depends on the nature of the interstellar medium-solar wind interaction. The charge of the grains couples them to the interstellar magnetic field (ISMF) resulting in some fraction of grains being excluded from the heliosphere while grains on the larger end of the size distribution, with gyroradii comparable to the size of the heliosphere, penetrate the termination shock. This results in a skewing the size distribution detected in the Solar System. We present new calculations of grain trajectories and the resultant grain density distribution for small ISDGs propagating through the heliosphere. We make use of detailed heliosphere model results, using three-dimensional (3-D) magnetohydrodynamic/kinetic models designed to match data on the shape of the termination shock and the relative deflection of interstellar H° and He° flowing into the heliosphere. We find that the necessary inclination of the ISMF relative to the inflow direction results in an asymmetry in the distribution of the larger grains (0.1 μm) that penetrate the heliopause. Smaller grains (0.01 μm) are completely excluded from the Solar System at the heliopause. [ABSTRACT FROM AUTHOR]

We present near-infrared images of the supernova remnant RCW 103 (G332.4-0.4) from the Two Micron All Sky Survey (2MASS). In all three 2MASS bands—J, H, K[sub s]—emission is detected, revealing a barrel-shaped, shell-like morphology. However, the J and H band shells are displaced with K[sub s] band shell. The J and H band emission are mostly from [Fe II] lines while the K[sub s] band emission is mostly from molecular hydrogen, as inferred from previous near-infrared spectroscopy. The 2MASS images show that the displacement between the [Fe II] and H[sub 2] is not just due to a projection effect; instead, it appears that the layers emitting [Fe II] and H[sub 2] lines are intrinsically double shells. We compared the 2MASS images with radio and X-ray images at comparable resolutions. The X-ray and radio shells coincide with the J and H band shells, while the K[sub s] band shell is located outside of the shock front. We discuss the origin of the molecular hydrogen shell in terms of a magnetic precursor or excitation by a radiative precursor. We also discuss the ISM environment of RCW 103 using physical parameters inferred from near-infrared lines. [ABSTRACT FROM AUTHOR]

We present new infrared images of the prototype of galaxy compact groups, Stephan’s Quintet (SQ), taken with Spitzer/MIPS at 24, 70 and 160 μm, and compare these with existing images at X-ray, UV/optical, radio wavelengths as well as with archival Spitzer/IRAC imaging at 8 μm. The new images reveal an extended (on scales of up to ca. 70 kpc) component of FIR emission which is roughly correlated with diffuse soft X-ray emission arising from the so-called SHOCK and HALO regions. A further interesting aspect of this study is the displacement of the main star formation sites from the central galaxy disks to the peripheries of the galaxies or to the intergalactic medium (IGM). [ABSTRACT FROM AUTHOR]