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[PCG20-05] Effect of Ice Sublimation and Condensation on Crystalline abundance of a Protoplanetary Diisk
Crystalline silicates are observed in outer cold regions of a protoplanetary disk although they would be formed by annealing of amorphous precursors in the inner regions of the disk. Although some studies showed that small crystalline silicate dust could be transported to disk outer region, the crystallinity of dust considering size growth is not well-investigated. Arakawa et al. (2021) showed large crystalline silicates could be carried in an evolving disk due to disk wind. However, they did not consider the difference of stickiness between ice and silicate. On the other hand, although Okamoto & Ida (2022) showed the crystalline abundance increase due to higher stickiness of ice than silicate and decaying icy pebble flux, they did not consider size growth of silicate dust.
We performed a 3D Monte Carlo simulation of advection/diffusion of silicate particles in an expanding disk considering dust growth and evaporation and condensation of water. We assumed stickiness of silicate is less than ice, and when particles collide faster than velocity for fragmentation, they are fragmented. We set “annealing line” by T = 1000 K and assume all amorphous precursors are annealed inside the snow line.
At first, icy pebbles including amorphous precursors grow up fast and drift inward. Then, icy pebbles pile up at snow line. As a result, most of silicate dust do not diffuse over snow line and more amorphous silicates are annealed. After that, due to the inward movement of snow line, some crystalline silicates can diffuse over snow line. Therefore, the crystallinity of silicates around 10 au is raised up to ~ 30% for 1 Myr. Finally, since new crystalline silicates are not formed due to the decrease in the disk temperature, crystallinity also decrease throughout the disk.
We performed a 3D Monte Carlo simulation of advection/diffusion of silicate particles in an expanding disk considering dust growth and evaporation and condensation of water. We assumed stickiness of silicate is less than ice, and when particles collide faster than velocity for fragmentation, they are fragmented. We set “annealing line” by T = 1000 K and assume all amorphous precursors are annealed inside the snow line.
At first, icy pebbles including amorphous precursors grow up fast and drift inward. Then, icy pebbles pile up at snow line. As a result, most of silicate dust do not diffuse over snow line and more amorphous silicates are annealed. After that, due to the inward movement of snow line, some crystalline silicates can diffuse over snow line. Therefore, the crystallinity of silicates around 10 au is raised up to ~ 30% for 1 Myr. Finally, since new crystalline silicates are not formed due to the decrease in the disk temperature, crystallinity also decrease throughout the disk.