SIMBAD references

BV CCD photometry of the young globular cluster NGC 1818 in the Large Magellanic Cloud was used to determine the age of this object and the slope of its initial mass function (IMF). Isochrones from four different stellar evolutionary models were fitted to the color magnitude diagram (CMD). Models including the effect of convective core overshooting give an age of 40Myr for NGC 1818 whereas those with a classical treatment of convective stellar cores give an age of about 20Myr. The luminosity function has a slope of γ=0.29±0.02 for all blue stars with -5.7<M_V<+2.3. Using appropriate isochrones the magnitudes of the main sequence stars were transformed to the corresponding masses and the slope of the IMF was determined. The resulting IMF slopes show some dependence on the input physics of the models but they are equal within the errors. The mean value for the slope of the IMF in the mass range 2-8M_☉ is x=1.1±0.3. This value is in good agreement with the results for other LMC clusters and the solar vicinity (x=1.35).