Epsilon Boötis (ε Boo, ε Boötis) is a double star in the northern constellation of Boötes. It has the traditional name Izar and was named Pulcherrima (most beautiful) by Otto Struve. The star system can be viewed with the unaided eye at night, but resolving the pair with a small telescope is challenging; an aperture of 76 mm (3.0 in) or greater is required.

In 1973, the Scottish astronomer and science fiction writer Duncan Lunan claimed to have managed to interpret a message caught in the 1920s by two Norwegian physicists that, according to his theory, came from a probe orbiting the Moon and sent there by the inhabitants of a planet orbiting Epsilon Boötis.The story was even reported in Time magazine.Lunan later withdrew his Epsilon Boötis theory, presenting proofs against it and clarifying why he was brought to formulate it in the first place but would later go on to revoke his withdrawal.