excited states in $^{57}$Zn covering an excitation energy of around 30 MeV. The density of states were chosen accordingly and contributions to GT strength from all excited states were incorporated in the rate calculation. The ASCII files of these GT strength functions are available and can be requested from the corresponding author.

$\beta^{+}$-Decay and Electron Capture Rates
============================================

At low stellar densities and temperatures, $\beta^{+}$-decay is the dominant mode for $^{57}$Zn to transform to $^{57}$Cu. For the calculation of the stellar weak interaction rate under corresponding physical conditions, it is of colossal importance to reproduce the measured GT strength distribution as compared to the total GT strength due to very strong energy dependence of the phase space factors. As discussed earlier the pn-QRPA model reproduced the low-lying strength for $^{57}$Zn better in comparison to the KB3G interaction used in the large shell model calculation. The stellar weak rates are sensitive to the location and structure of these low-lying states in daughter $^{57}$Cu. At the lowest temperature considered in this work (T$_{9} [K] = 0.01$), excited parent states are not appreciably populated (where T$_{9}$ is the stellar temperature in units of $10^{9} K$) , while at low density ($\rho
Y_{e}$ = 