Both stars share similar physical characteristics to the Sun, so they are considered solar analogs. Their stellar classification is nearly identical to that of the Sun. ζ1 has 96% of the Sun's mass and 84% of the Sun's radius. ζ2 is slightly larger and more luminous than ζ1, with 99% of the Sun's mass and 88% of the Sun's radius. The two stars are somewhat deficient in metals, having only 60% of the proportion of elements other than hydrogen and helium as compared to the Sun. For reasons that remain uncertain, ζ1 has an anomalously low abundance of beryllium. Two possible explanations are: during the star's formation it underwent multiple intense bursts of mass accretion from a rapidly rotating protostellar cloud, or else the star underwent rotational mixing brought on by a period of rapid rotation during the star's youth.