THE INITIAL MASS FUNCTION OF THE YOUNG CLUSTER NGC-1818 IN THE LARGE MAGELLANIC CLOUD

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 differe nt stellar evolutionary models were fitted to the color magnitude diag ram (CMD). Models including the effect of convective core overshooting give an age of 40 Myr for NGC 1818 whereas those with a classical tre atment of convective stellar cores give an age of about 20 Myr. The lu minosity function has a slope of gamma = 0.29 +/- 0.02 for all blue st ars with -5.7 < M(V) < +/- 2.3. Using appropriate isochrones the magni tudes of the main sequence stars were transformed to the corresponding masses and the slope of the IMF was determined. The resulting IMF slo pes show some dependence on the input physics of the models but they a re equal within the errors. The mean value for the slope of the IMF in the mass range 2 - 8 M. is re = 1.1 +/- 0.3. This value is in good ag reement with the results for other LMC clusters and the solar vicinity (x = 1.35).