The fate of icy pebbles undergoing sublimation in protoplanetary discs

Icy pebbles may play an important role in planet foation close to the water ice line of protoplanetary discs. There, dust coagulation is more efficient and recondensation of vapour on pebbles may enhance their growth outside the ice line. Previous theoretical studies showed that disruption of icy pebbles due to sublimation increases the growth rate of pebbles inside and outside the ice line, by freeing small silicate particles back in the dust reservoir of the disc. However, since planet accretion is dependent on the Stokes number of the accreting pebbles, the growth of planetesimals could be enhanced downstream of the ice line if pebbles are not disrupting upon sublimation. We developed two experimental models of icy pebbles using different silicate dusts, and we exposed them to low-temperature and low-pressure conditions in a vacuum chamber. Increasing the temperature inside the chamber, we studied the conditions in which pebbles are preserved through sublimation without disrupting. We find that small silicate particles (