Chemical abundances of OB stars in the Cepheus OB2 association

LTE and non-LTE abundances of carbon, nitrogen, oxygen, and silicon, as well as LTE abundances of Fe, are presented from analyses of C II, N II, O II, Si III, and Fe III lines in the spectra of eight main-sequence OB stars in the Cep OB2 association. We find that the chemical composition of the studied stars in this association is very homogeneous: the abundances of all elements analyzed do not show significant variations, and the observed abundance dispersions can be explained in terms of the uncertainties in the analysis. The abundance results indicate that this association is slightly metal poor ([Fe/ H] = -0.3) with the abundances of all studied elements being subsolar by roughly the same amount.