2021MNRAS.501.5468S

Using the analytical solution of the heat diffusion equation, we calculate the components of the thermal stress tensor and analyse the process of thermal destruction of bodies consisting of crystalline ice with radii ranging from 10 m to 10 km around KIC 8462852. As a body approaches the star in a high-eccentricity orbit, compressive stresses increase on its surface, making tensile stresses increase in its interior and causing catastrophic body destruction. The processes of destruction near the surface of bodies that occur as a result of compressive stress and contribute to the appearance of coma are most severe in large bodies (10 km or more). We show that, for bodies with radii from 20 m to 10 km, internal tensile strengths exceed the limit of material strength at different distances from the star. Bodies with a size of r ≃ 1.8-2.1 km are among the first to experience catastrophic destruction, being at a distance of 80-100 au from the star. Subsequent cascading destruction of fragments can lead to the formation of dust. Closest to the star, being at a distance of 7.44 au, both the biggest and smallest bodies with a radius of more than 10 km and less than 20 m, respectively, begin to break apart. The infalling thermally destroyed body (ITDB) mechanism is capable of explaining the main details of both the short-term and long-term photometric behaviour of KIC 8462852.