A note on the snow line in protostellar accretion disks

Abstract— The temperature of ice grains in a protostellar disk is computed for a series of disk models. The region of stability against sublimation is calculated for small ice grains composed of either pure ice or “dirty” ice. We show that in the optically thin photosphere of the disk the gas temperature must be around 145 K for ice grains to be stable. This is much lower than the temperature of 170 K that is usually assumed.