2 NITROGEN RICH MAIN-SEQUENCE B-STARS IN THE SMALL MAGELLANIC CLOUD CLUSTER, NGC-330

High resolution spectra of two narrow lined main-sequence B-type stars in the SMC cluster NGC 330 are analysed using LTE methods to obtain t heir chemical compositions relative to SMC and galactic field B-stars. It is found that these stars, designated A01 and B04, have parameters ({T-eff, log g}) of {26 000, 3.8} and {23 000, 3.6} respectively and, surprisingly, nitrogen abundances approximately 0.8 dex higher than o ther SMC main-sequence B-stars. There is also marginal evidence for mo derate deficiencies of both oxygen and silicon consistent with the pre viously reported low metallicity of this cluster. Since supergiants in the cluster do not exhibit such a large nitrogen enrichment it is arg ued that A01 and B04 have had their surface chemical compositions modi fied either as the result of binary mass transfer or due to rotational ly induced turbulent diffusion. For both scenarios the absence of a co mplementary carbon deficiency is surprising. These findings, combined with previous observations of the most lumninous main-sequence stars i n the cluster, imply that the upper main-sequence of the cluster is di fficult to understand in terms of standard stellar evolution models.