Thermal stresses in small meteoroids

Abstract

Aims. We evaluate thermal stresses in small, spherical, and homogeneous meteoroids with elastic rheology and regular rotation. The temperature variations are caused by the absorbed sunlight energy being conducted into the interior layers of the body. Our model assumes arbitrary thermal conductivity value, but restricts itself to a linearized treatment of the boundary conditions of the heat diffusion problem. We consider the diurnal insolation cycle only as if the body were in a fixed position along its heliocentric orbit. This constrains the upper limit to the object size to which our modeling is applicable. Methods. We derive analytical expressions for the components of the thermal stress tensor throughout the body. Using two sets of material properties (ordinary and carbonaceous chondrites), we study the conditions required for material failure caused by thermal stress leading to fission. Results. Our results indicate that the onset of thermal failure in the meteoroid depends on a number of parameters including the heliocentric distance, the size, the rotation frequency, and the orientation of the spin axis with respect to the solar direction. In our case, we find large, centimeter-to meter-size, slowly rotating meteoroids or those with a spin axis pointing towards the Sun or both, are the most susceptible to the thermal bursting. This may have implications for the (i) size distribution of meteoroids in various streams depending on their heliocentric orbit and the physical characteristics of their parent bodies; (ii) orbital distribution of sporadic complexes of meteoroids in the planet-crossing zone; and/or (iii) fate of fragments released during comet disintegration events, especially those with low perihelia (e.g., Kreutz class).

Grain‐scale thermoelastic stresses and spatiotemporal temperature gradients on airless bodies, implications for rock breakdown

“…While spatial temperature gradients at the macroscopic scale may be useful [ Čapek and Vokroulichý , ] for investigating macroscopic processes, our results suggest that at grain scale they are not. Neither the grain‐ or domain‐scale temperature gradient correlates with the location or time of peak thermal stresses within a microstructure.…”

Supercatastrophic Disruption of Asteroids in the Context of SOHO Comet, Fireball, and Meteor Observations

“…Lamy et al (2013) say "the real surprise comes from many comets (mostly from the Machholz group) with nearly 'flat' light curves.". This could be accounted for by inhomogeneities in the meteoroid environment, such that the meteoroid flux closer to the Sun is less than further away, owing either to how the meteoroids were deposited by their parents, their subsequent dynamical evolution, or their destruction by thermal processes ( Čapek & Vokrouhlický 2010) or collisions with other meteoroids.…”

Space-Based Thermal Infrared Studies of Asteroids

“…Delbó et al (2014) posit that thermal cracking plays a key role in regolith production, with an erosion and destruction process that preferentially affects more fragile, low-albedo, carbonaceous objects as they approach the Sun; see alsǒ Capek & Vokrouhlický (2010, 2012.…”

“…The albedo-insensitive sample from Mainzer et al (2012c) suggests a paucity of NEOs with low albedos at low perihelion distances, although the sample size is small. Delbó et al (2014) posit that thermal cracking plays a key role in regolith production, with an erosion and destruction process that preferentially affects more fragile, low-albedo, carbonaceous objects as they approach the Sun; see also Čapek & Vokrouhlický (2010Čapek & Vokrouhlický ( , 2012.…”