  High-resolution mid-infrared observations of astrospheres show that many of
them have filamentary (cirrus-like) structure. Using numerical models of dust
dynamics in astrospheres, we suggest that their filamentary structure might be
related to specific spatial distribution of the interstellar dust around the
stars, caused by a gyrorotation of charged dust grains in the interstellar
magnetic filed. Our numerical model describes the dust dynamics in astrospheres
under an influence of the Lorentz force and assumption of a constant dust
charge. Calculations are performed for the dust grains with different sizes
separately. It is shown that non-monotonic spatial dust distribution (viewed as
filaments) appears for dust grains with the period of gyromotion comparable
with the characteristic time scale of the dust motion in the astrosphere.
Numerical modelling demonstrates that number of filaments depends on
charge-to-mass ratio of dust.
