The mass surface density in the local disk and the chemical evolution of the Galaxy

We have studied the effect of adopting different values of the total baryonic mass surface density in the local disk at the present time, Sigma(R., t(Gal)), on the model of the chemical evolution of the Galaxy. We have compared our model results with the G dwarf metallicity distribution, the amounts of gas, stars, and stellar remnants, the infall rate, and the supernova rate in the solar vicinity, and with the radial abundance gradients and gas distribution in the disk. This comparison strongly suggests that the value of Sigma(R., t(Gal)) that best fits the observational properties should lie in the range 50-75 M. pc(-2) and that values of the total disk mass surface density outside this range should be ruled out.