Eta Boötis is a candidate binary star system in the constellation of Boötes. Its name is a Bayer designation that is Latinized from η Boötis, and abbreviated Eta Boo or η Boo. This system is visible to the naked eye as a point of light with an apparent visual magnitude of 2.68. Based on parallax measurements obtained during the Hipparcos mission, it is approximately 37 light-years (11 pc) distant from the Sun. It is drifting closer with a radial velocity of −5.3 km/s. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified. It forms a double star with the star BD+19 2726. As a constituent of a double pair, Eta Boötis is also designated WDS J13547+1824A, with its two components being designated Aa (formally named Muphrid , the traditional name for the entire system) and Ab. (As part of a binary pair, they are also designated Eta Boötis A and B, respectively.) BD +19 2726 is also designated WDS J13547+1824B.

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