Chemo-Spectral Evolution of the Milky Way and of Spiral Disks

Abstract

Our model and its application to the Milky Way are discussed in detail in Boissier & Prantzos (1998). The stellar yields of Woosley & Weaver (1995) are used to compute the chemical evolution, while the spectral one is coherently followed with the stellar evolution tracks of the Geneva group (Schaller et al. (1992), Charbonnel et al. (1996)) covering all the evolutionary phases (MS to AGB) for several metallicities and the synthetic stellar spectra library of Lejeune et al. (1997) providing spectra as a function of (T _eff , log(g), Z). Extinction from dust is calculated as in Guiderdoni & Rocca-Volmerange (1987) with the geometry of stars and dust of Xu et al. (1997). The Star Formation Rate is assumed to be locally a Schmidt Law (αΣ ^1.5 _g ), and to depend on galactic radius (α 1/R) according to the theory of star formation induced by the passage of density waves -see Prantzos fc Aubert (1995) and references therein. The Initial Mass Function is the one of Kroupa et al. (1993). Finally, an exponential infall with time-scale τ=7 Gyr in the Solar neighborhood is assumed, to account for the local G-Dwarf distribution. Inside-out disk formation of the disk is assumed via τ(R).