Cor Caroli (Alpha Canum Venaticorum) is the brightest star in the northern constellation Canes Venatici. Cor Caroli marks the northern vertex of the Diamond of Virgo asterism. It is a binary star with a combined apparent magnitude of 2.81, approximately 110 light years from Earth.

The stars in this binary have a strong magnetic field, which is believed to produce starspots of enormous extent. Due to these starspots the brightness of the stars vary considerably during their rotation, varying between magnitude +2.84 and +2.98 with a period of 5.47 days.





In the Star Trek: The Next Generation episode "Allegiance", Cor Caroli  was visited by the USS Enterprise-D and was the location of an outbreak of Phyrox plague, which the USS Enterprise-D successfully eliminated.

The name Cor Caroli means Charles' heart, and was named by Sir Charles Scarborough in honour of Charles I who was executed in the aftermath of the English Civil War.
The planet Cor Caroli V in "Allegiance"