Evolutions of the temperature in panel a and the density in panel b of the gas surrounding one-micron grains in the collapse simulation of Bhandare et al. (2024). The 55 trajectories selected from the simulation are those where the grains experience a maximum temperature between 1000 and 2000 K. Each trajectory starts at a temperature of 600 K. The red solid line represents the trajectory chosen in this article to compute the dust evolution. The grain position evolution is shown in Fig. 9.