8 6 ▁times ▁the ▁Sun ' s ▁radius . ▁The ▁star ▁is ▁radi ating ▁ 3 . 3 9 ▁times ▁the ▁solar ▁lum inos ity ▁from ▁its ▁photos phere ▁at ▁an ▁effective ▁temperature ▁of ▁ 6 , 0 9 1   K . ▁ ▁This ▁system ▁was ▁in ▁ 1 9 9 1 ▁a ▁test ▁case ▁for ▁the ▁Z eta ▁Her cul is ▁moving ▁group , ▁of ▁low ▁met all icity ▁stars ▁with ▁ 5 ▁billion ▁years ▁of ▁age . ▁This ▁group ▁includes ▁besides ▁Z eta ▁Her cul is : ▁ δ ▁Tri ang uli , ▁ ζ ▁Ret icul i , ▁ 1 ▁H yd ra e , ▁Gl ▁ 4 5 6 , ▁Gl ▁ 6 7 8 , ▁and ▁Gl ▁ 9 0 7 9 . ▁ ▁In ▁ 1 9 9 8 , ▁using ▁the ▁European ▁Southern ▁T eles cope ▁in ▁Chile , ▁a ▁planet ▁was ▁announced ▁to ▁be ▁orbit ing ▁the ▁star . ▁This ▁team ▁ret ract ed ▁this ▁claim ▁in ▁ 2 0 0 2 , ▁but ▁found ▁a ▁different ▁period icity ▁of ▁ 7 ▁days ▁possibly ▁due ▁to ▁stell ar ▁rotation . ▁ ▁See ▁also ▁▁ ▁Z eta ▁Her cul is ▁ ▁References ▁ ▁Category : F - type ▁main - sequence ▁stars ▁Category : Z eta ▁Her cul is ▁Mov ing ▁Group ▁Pav on is , ▁Ph i 2 ▁Category : P avo ▁( const ell ation ) ▁ 0 7 9 4 . 2 ▁and ▁ 9 7 0 1 ▁ 1 9 6