Physical parameters and chemical abundances of δδ Ceti

A detailed spectroscopic study of a ββ Cephei variable star, δδ Ceti, is presented. Physical fundamental parameters are estimated from the best fitting of 26 neutral helium lines and Balmer profiles: effective temperature, superficial gravity and projected rotation velocity. Non-LTE abundances of He, C, N, O, Ne, Mg, Al, Si, P, S, Ar and Fe are achieved using model atmospheres with updated atomic data. Our analysis show an N-enrichment and Fe overabundance, with [O/Fe]≅≅ −0.73 dex, confirming this object to be a metal-rich star, which is a requirement for the κκ-mechanism to trigger the pulsations observed in ββ Cephei stars.

► We present medium resolution spectroscopic observations made at ESO/La Silla. ► Physical parameters of the photosphere and chemical abundances were performed. ► Results show an N-enrichment and Fe overabundance with [O/Fe] = −0.73 dex.