▁of ▁hydro gen ▁at ▁its ▁core ▁and ▁evol ved ▁into ▁a ▁giant ▁star . ▁It ▁now ▁has ▁a ▁radius ▁more ▁than ▁ten ▁times ▁the ▁radius ▁of ▁the ▁Sun . ▁Comp ared ▁to ▁the ▁Sun , ▁this ▁star ▁appears ▁def ic ient ▁in ▁elements ▁other ▁than ▁hydro gen ▁and ▁hel ium — what ▁astronom ers ▁term ▁the ▁star ' s ▁met all icity . ▁The ▁outer ▁en velope ▁of ▁this ▁star ▁has ▁an ▁effective ▁temperature ▁of ▁ 4 , 8 4 7   K , ▁which ▁is ▁what ▁gives ▁it ▁the ▁characteristic ▁yellow ▁h ue ▁of ▁a ▁G - type ▁star . ▁ ▁The ▁secondary ▁component ▁has ▁a ▁stell ar ▁classification ▁of ▁G 0   V , ▁which ▁suggests ▁it ▁is ▁a ▁main ▁sequence ▁star ▁that ▁may ▁be ▁similar ▁in ▁physical ▁properties ▁to ▁the ▁Sun . ▁The ▁apparent ▁visual ▁magnitude ▁of ▁this ▁star ▁is ▁ 7 . 8 1 , ▁making ▁it ▁much ▁less ▁l umin ous ▁than ▁the ▁primary ▁component . ▁ ▁References ▁ ▁External ▁links ▁ ▁H R ▁ 5 6 8 1 ▁ ▁C CD M ▁J 1 5 1 5 6 + 3 3 1 9 ▁ ▁Image ▁D elta ▁Bo öt is ▁ ▁Boot is , ▁ 4 9 ▁ 1 3 5 7 2 2 ▁ 0 7 4 6 6 6 ▁Boot is , ▁D elta ▁Category : Bo ö tes ▁Category : Binary ▁stars ▁Category : G - type ▁gi ants ▁Category : G - type ▁main - sequence ▁stars ▁ 5 6 8 1 ▁Category