Astrophysical bounds on superlight gravitinos

We derive the allowed mass range for the superlight gravitino present in a large class of supersymmetric models from the observed luminosity from Supernova 1987A. We find that for photino masses of order 100 GeV, the mass range $2.6\times 10^{-6} eV \leq m_{\tilde{g}} \leq 2.2\times 10^{-8} eV$ for the gravitino $\tilde{g}$ is excluded by SN1987A observations. Unlike the bounds on $m_{\tilde{g}}$ from nucleosynthesis, the bounds in the present paper do not depend critically on the uncertainties of the observational input.