Abstract
Conventional theoretical calculations of nuclear matter properties based on mean-field approaches fail to give the correct low-temperature, low-density limits for composition and symmetry energy which are governed by the appearance of clusters. Data from heavy-ion collisions can be used to probe clusterization and the symmetry energy at subsaturation densities. From the data, in medium cluster binding energies and Mott points for d, t, $^{3}$He and clusters produced in low density nuclear matter and may be extracted. The low densities and moderate temperatures explored are comparable to those expected for the neutrinosphere in a supernova explosion. These data can be used to test astrophysical equations of state at low density.