Cor Caroli

Cor Caroli, also called Alpha Canum Venaticorum, binary star located 110 light-years from Earth in the constellation Canes Venatici and consisting of a brighter component (A) of visual magnitude 2.9 and a companion (B) of magnitude 5.5. It is the prototype for a group of unusual-spectrum variable stars that show strong and fluctuating absorption lines of silicon, chromium, strontium, or certain rare earths. Europium apparently is concentrated around one magnetic pole, chromium around the other. Cor Caroli (Latin for “Heart of Charles”) was named after the executed English king Charles I by Sir Charles Scarborough, physician to Charles II, who said that it shone brightly on May 29, 1660, when Charles II returned to London to restore the monarchy.