Is Mizar a double star?
Daniel Rodriguez
Published Mar 08, 2026
Is Mizar a double star?
Mizar is a visual double with a separation of 14.4 arcseconds, each of which is a spectroscopic binary. Its combined apparent magnitude is 2.04. The two visible stars are referred to as ζ 1 and ζ 2 Ursae Majoris, or Mizar A and B.
What is the meaning of Mizar?
The traditional name Mizar derives from the Arabic المئزر miʼzar meaning ‘apron; wrapper, covering, cover’. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars.
What is the difference between Mizar and Alcor?
Mizar and Alcor are at the upper right. The multiple star system of Mizar (the double star on the right) and Alcor (left). The unrelated, fainter star Sidus Ludovicianum can be seen lower down. Mizar is a visual double with a separation of 14.4 arcseconds, each of which is a spectroscopic binary. Its combined apparent magnitude is 2.04.
How far away are Mizar and Alcor?
Mizar and companion Alcor in a 4.5-inch (11.4-cm) telescope at 45x. Both Mizar and Alcor lie about 80 light-years from Earth and share a common proper motion across the sky, yet their great distance from one another made it difficult to determine if they formed a true gravitationally-bound binary star.
What is the scientific name for Mizar?
Mizar / ˈmaɪzɑːr / is a second- magnitude star in the handle of the Big Dipper asterism in the constellation of Ursa Major. It has the Bayer designation ζ Ursae Majoris ( Latinised as Zeta Ursae Majoris ). It forms a well-known naked eye double star with the fainter star Alcor, and is itself a quadruple star system.
What is the difference between Mizar Aa and Mizar AB?
The stars’ masses differ only very slightly – Mizar Aa has 2.2224 solar masses and Mizar Ab has 2.2381 – and reflect the slight variations in the stars’ radial velocities. The stars orbit each other with a period of 20.586 days (20 days, 12 hours and 55 minutes).