We present phase-resolved spectroscopy and extensive survey photometry of the detached eclipsing binary system XY Cet , which is composed of two metallic-lined stars .
We measure their masses to be 1.773 \pm 0.016 and 1.615 \pm 0.014 { M } _ { \odot } and their radii to be 1.873 \pm 0.035 and 1.773 \pm 0.029 { R } _ { \odot } , resulting in logarithmic surface gravities of 4.142 \pm 0.016 and 4.149 \pm 0.014 ( cgs ) .
We determine effective temperatures of 7870 \pm 115 and 7620 \pm 125 K. The projected rotational velocities are 34.4 \pm 0.4 and 34.1 \pm 0.4 km s ^ { -1 } , which are close to synchronous .
Theoretical models can not match all of these properties , but come closest for a solar helium and metal abundance and an age in the region of 850 Myr .
We obtain the individual spectra of the two stars by the spectral disentangling method , and compare them to synthetic spectra calculated for the measured effective temperatures and a solar chemical composition .
Both stars show enhanced abundances of iron-group elements and clear deficiencies of Ca I and Sc II , confirming their classification as Am stars .
We also find strong overabundances of Zr II and the rare-earth species La II , Ce II and Nd II , a hallmark of chemically peculiar A stars .
XY Cet is a prime candidate for detailed spectroscopic analyses of metallic-lined stars whose masses and radii are known to accuracies of 1–2 % .