▁the ▁same ▁size . ▁ ▁With ▁an ▁effective ▁temperature ▁of ▁ 5 6 2 7 ▁K , ▁Ke pler - 1 0 ▁is ▁cool er ▁than ▁the ▁Sun . ▁The ▁star ▁is ▁also ▁metal - po or ▁and ▁far ▁older : ▁its ▁met all icity ▁is ▁measured ▁at ▁[ Fe / H ] ▁= ▁− 0 . 1 5 ▁( 2 9 % ▁less ▁iron ▁than ▁in ▁the ▁Earth ' s ▁Sun ). ▁Ke pler - 1 0 ▁has ▁a ▁measured ▁age ▁of ▁approximately ▁ 1 0 . 6 ▁billion ▁years . ▁ ▁Ke pler - 1 0 ▁has ▁an ▁apparent ▁magnitude ▁of ▁ 1 1 . 2 , ▁which ▁means ▁that ▁the ▁star ▁is ▁invisible ▁to ▁the ▁n aked ▁eye ▁from ▁the ▁perspective ▁of ▁an ▁observer ▁on ▁Earth . ▁ ▁Character istics ▁Ke pler - 1 0 c ▁is ▁the ▁outer most ▁of ▁the ▁two ▁known ▁plan ets ▁of ▁Ke pler - 1 0 , ▁comple ting ▁one ▁orbit ▁of ▁the ▁star ▁every ▁ 4 5 . 2 9 4 8 5 ▁days ▁at ▁a ▁distance ▁of ▁ 0 . 2 4 0 7 ▁A U . ▁The ▁inner ▁planet , ▁Ke pler - 1 0 b , ▁is ▁a ▁rock y ▁planet ▁that ▁or bits ▁every ▁~ 0 . 8 ▁days ▁at ▁a ▁distance ▁of ▁ 0 . 0 1 6 8 4 ▁A U . ▁Ke pler - 1 0 c ' s ▁equilibrium ▁temperature ▁is ▁estimated ▁at ▁ 5 8 4 ▁K , ▁almost ▁four ▁times ▁hot ter ▁than