Resumen
We presented non-gray pre-main sequence evolutionary tracks and isochrones in theoretical and observational Hertzsprung-Russel diagrams. Theoretical tracks were generated by ATON2.4 code (Landin et al., 2006, A&A, 456, 269) for the mass interval of 0.15-3.8 M_{odot} and metallicities of [Fe/H]=-0.24, 0.0 and +0.37. By using color-temperature relations and bolometric corrections in UBVRIJHKL (Bessel et al. 1998, A&A, 333, 231) and BVRI (VadenBerg & Clem, 2003, AJ, 126, 778) photometric systems, we converted theoretical tracks and isochrones to their counterparts in color-magnitude diagrams (CMD). Tracks in theoretical and observational Hertzsprung-Russel diagrams show the well known shift, in main sequence, to smaller temperatures (or higher V-I) with increasing metallicity. The tracks obtained with both transformations behave roughly the same way for larger masses, but for M<0.8 M_{odot } Bessel's transformations return B-V colors in disagreement with observations and theory especially for cool stars and it can be due to the opacity incompleteness in the blue and UV. Finally, our tracks and isochrones in CMD were used to investigate the evolutionary status of a multiple system and a young cluster. η Mus is a 22 Myr old system, consisting of two late B-type stars of 2.9 M_{odot } each and a 0.79 M_{odot } pre-main sequence star. We estimated that NGC 2264 stars have masses, mainly, in the range 0.1-0.6M_{odot} and the mean age of stars' cluster is 3.5 Myr, what is in agreement with other works.
