DESTRUCTION OF SMALL BODIES COMPOSED OF SILICATES BY THERMAL STRESSES. THERMAL EMISSION OF DISRUPTION PRODUCTS

This study investigates the influence of thermal stresses on the destruction of small rocky bodies-meteoroids and asteroids-as they approach the Sun. Based on an analytical solution of the heat diffusion equation, temperature profiles and thermally induced mechanical stresses are computed for various silicate materials, including basalt, carbonaceous and ordinary chondrites, as well as terrestrial rocks and minerals. It is shown that the degree of heating and the character of thermal stresses depend on the size of the body: meteoroids smaller than 10 cm are heated uniformly, while in bodies larger than 10 meters, heating is confined to near-surface layers. The calculations are performed for bodies moving from 86 AU (outer Solar System) to 0.03 AU (). Critical disruption distances are determined as follows: basaltic bodies-between 0.03 and 2.5 AU (from the Sun to the Main Asteroid Belt), carbonaceous chondrites-up to 2 AU (within the orbit of Mars), ordinary chondrites-up to 1 AU (within the orbit of Earth), while rocks and minerals remain stable up to temperatures of ~1000 K (approximately 0.17–0.2 AU, between the Sun and Mercury). Small bodies (up to 10 meters) may undergo thermal fragmentation in the region between the orbits of Mars and Mercury, forming dust envelopes. Larger bodies can also become thermally destabilized: carbonaceous chondrites (~40 m) and basalts (~80 m) near Earth’s orbit, ordinary chondrites (10–50 m) between the orbits of Venus and Earth. Very large bodies (over 100 meters) disintegrate closer to the Sun, producing dust clouds observable in optical and infrared wavelengths. The primary sources of these bodies are the Main Asteroid Belt and the Kuiper Belt. This work emphasizes the significance of thermal processes in the evolution and observational characteristics of small bodies in the Solar System.