Manifestation of the stellar wind cycle in infrared images: Example of the heliosphere

Abstract

The regions in which stellar winds interact with the interstellar medium, also known as astrospheres, can be observed in detail through the thermal emission of the interstellar dust particles, resided in plasma. Interstellar dust is also directly observed in the vicinity of the Sun with dust detectors onboard spacecraft, and it is known to be affected by the interplanetary magnetic field. The main goal of this work is to show how the change in the interplanetary magnetic field with the solar cycle affects the infrared picture of the heliosphere. To compose a synthetic intensity map of the interstellar dust thermal emission, we used the Monte Carlo method to calculate the distribution of the dust particles inside the heliosphere. We considered the effects of the heliosphere boundaries and the non-stationary current sheet. The change in the Parker magnetic field caused by the solar activity cycle leads distinguishable features in the mid-infrared emission maps of the heliosphere. The distribution of the interstellar dust in the vicinity of the Sun we calculated suggests that small particles linger outside of the heliosphere, and medium-size particles are mostly affected by the changing interplanetary magnetic field, which leads to number density waves in the tail region of the heliosphere. Finally, large particles form a bulge behind the Sun.