Helium abundance in the atmospheres of the stars in the clusters NGC 869, 884, and 2264.

Effective temperature T_e, surface gravity lg g, helium abundance ɛ(He) in the atmospheres, rotation velocity V sin i are determined by the model atmosphere method for 23 B stars in the clusters NGC 869, 884, 2264. Analysis of the helium abundance supplemented with the results obtained previously by the authors (1986) for 46 B stars has led to a statistically confident inference of the absence of significant differences in the average helium abundance from cluster to cluster.