Chromospherically active stars. XVII. The double-lined binary 54 Camelopardalis (AE Lyncis)

New spectroscopic observations of the double-lined chromospherically active binary 54 Camelopardalis (=AE Lyncis) have been obtained, resulting in improved orbital elements and the determination of the fundamental properties of the system. 54 Cam has a period of 11.06794 days, an eccentricity of 0.125, and a mass ratio of 0.9945. The spectral types are F8 IV-V and G5 IV, positioning the components on opposite sides of the Hertzsprung gap. From a comparison with theoretical evolutionary tracks, the masses are estimated to be 1.60 and 1.59 M. for the G and F stars, respectively, while the radii are 3.7 and 3.2 R.. Only the G star is chromospherically active. 54 Cam is particularly interesting since the F star is the brighter star at blue and red wavelengths, but the G star is slightly more massive and evolved. Both stars appear to be pseudosynchronously rotating, and the orbital and rotational inclinations are aligned. The lithium abundances of the two components are significantly different but consistent with standard theory, supporting the conclusion that both stars are more massive than the lithium-dip stars.