Evolutionary Status of the Ap Stars HD 110066 and HD 153882

Abstract

We present the results of our determination of the fundamental atmospheric parameters for the magnetic chemically peculiar Ap stars HD 110066 (AX CVn) and HD 153882 (V451 Her). The determination of the atmospheric parameters ( $$T_{\textrm{eff}}$$ , $$\textrm{log}{g}$$ , $$R/R_{\odot}$$ , and $$L/L_{\odot}$$ ) is based on a self-consistent analysis of high-resolution spectra (ESPaDOnS with $$R=65\,000$$ ) and the observed flux distribution in a wide spectral range. We have derived the radial magnetic field components $$B_{r}=4015\pm 180$$ G for HD 110066 and $$B_{r}=3800\pm 200$$ G for HD 153882 from the observed line splitting and magnetic differential broadening. We have analyzed the chemical composition and the vertical distribution (stratification) of Fe and Cr in atmospheric depth, because the lines of these elements make the greatest contribution to the absorption and stratification affects the distribution of the outgoing flux. We have constructed model atmospheres and determined the evolutionary status of these stars by taking into account the anomalous chemical composition and stratification. The positions of HD 110066 and HD 153882 on the Hertzsprung–Russell diagram confirm the observed decrease in the magnetic field strength with stellar age for stars with masses greater than 2.5 $$M_{\odot}$$ .