Dust growth is one of the key processes leading to planet formation in protoplanetary disks. Centimeter-sized dust grains—pebbles—are essential for the formation of planetesimals through streaming instability and play a crucial role in the formation of protoplanetary cores, giant planets, and the enrichment of their atmospheres with chemical elements. This study investigates the impact of luminosity outbursts on the amount of pebbles and icy mantles in a protoplanetary disk. We perform global simulations of the formation and evolution of a self-gravitating, viscous protoplanetary disk using the two-dimensional thin-disk hydrodynamic code FEOSAD, which self-consistently produces luminosity outbursts. The model includes thermal balance, dust evolution and its interaction with gas, the development of magnetorotational instability, adsorption and desorption of four volatile species (HO, CO, CH, and CO), and the feedback of icy mantles on the fragmentation properties of dust aggregates. Our results show that luminosity outbursts have a stronger impact on the snowlines of CO, CH, and CO than on the water snowline. This is because the HO snowline resides in a region dominated by viscous heating during the early stages of disk evolution, whereas the snowlines of the other molecules lie in regions where stellar irradiation dominates the thermal structure, making them more sensitive to temperature variations induced by the outbursts. Nevertheless, luminosity outbursts lead to a twofold reduction in the total amount of pebbles in the disk due to the fragmentation of dust aggregates into monomers following the loss of water ice, which acts as a binding agent. The reformation of pebbles occurs over several thousand years after the outburst, primarily through collisional coagulation. The characteristic timescales for pebble recovery significantly exceed the freezing timescales of water ice. The desorption of icy mantles occurs in a highly non-axisymmetric and intrinsically two-dimensional region of the disk, which is linked to the formation of spiral substructures during the early evolution of a gravitationally unstable disk.
A. P. Topchieva (Wed,) studied this question.