The star Zeta Ursae Majoris, an A1 dwarf of magnitude 2.2, distance 86 l.y. It forms a naked-eye double with Alcor, but the two are not a binary pair. However, a closer companion of magnitude 4.0 is connected. In 1889 E. C. Pickering found that Mizar is a spectroscopic binary. Mizar was therefore the first telescopic binary and the first spectroscopic binary to be discovered. The 4th-magnitude companion is also a spectroscopic binary.
Subjects: Astronomy and Astrophysics.