Extended Data Figure 1: Sketch of the observed phenomenon.
From: Imaging the water snow-line during a protostellar outburst
a, During quiescence, the water snow-line around stars of Solar masses is located 5 au or less from the star, where the temperature of the disk reaches the sublimation point of water. b, During protostellar accretion outbursts, this line moves out to more than 40 au, where it can be detected. Outward of the snow-line, grain growth is promoted by the high coagulation efficiency of ice-covered grains (brown and blue concentric circles). Inward of this line, dust production is promoted by the high fragmentation efficiency of bared silicates (brown circles). This results in the observed break in the disk intensity profile, a steep reduction in the 1.3-mm dust opacity, and a sharp increase in the spectral index across the snow-line.
