Effect of the Heliosheath hot plasmas on the interstellar grain heating

The dust grains play a major role in the infrared emission from the interstellar medium (ISM), even though they comprise only ~1% of its total baryonic mass. Therefore the precise knowledge on the heating mechanism of the interstellar dust grains is a key to understanding the energy balance and the dynamics in the ISM. The infrared emission from the local interstellar dust is mainly caused by absorbing the energy from the starlight, with a small contribution from the collisions with local hot plasmas. However, it has been difficult to quantitatively estimate the plasma collision effect on the infrared radiation field because the local plasma properties are not well understood. The measurements of energetic neutral atoms (ENAs), brought by the Interstellar Boundary Explorer (IBEX) since 2008, provide us with a unique global mapping of a local hot plasma parameters in the Heliosheath. In this study, we present a realistic model of the grain heating rate by using the local ENA information from IBEX, such as energy spectra and the plasma pressure, and examine the role of hot plasmas in heating the local interstellar grains.