Star profile
Zeta Ursae Majoris
Binary systemWhat is Zeta Ursae Majoris
Zeta-2 Ursae Majoris is Alcor, the small naked-eye companion to Mizar in the handle of the Big Dipper. For centuries it was a classic eye test: splitting the pair was a rite of passage among Turkish, Arab and European peoples. Itself a binary, sitting 79 light-years away, Alcor and Mizar together form one of the most thoroughly studied stellar groupings in the northern sky.
Where it is and when to see it
Zeta Ursae Majoris lies in the northern celestial hemisphere. It is visible to the naked eye under a dark sky. Its best month of the year is March, when it culminates around midnight.
- From London it never sets and culminates about 87° up.
- From New York it never sets and culminates about 76° up.
- From Sydney it culminates about 1° above the horizon.
It can be seen from anywhere north of 35° S.
It ranks no. 19 in brightness among the 124 stars of Ursa Major in our catalogue. To find it, start from Alioth, the brightest: it lies about 4° away (a fist at arm's length covers about 10°).
The light you see today left it about 79 years ago.
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Astronomical data for Zeta Ursae Majoris
- Constellation
- Ursa Major
- Apparent magnitude
- 3.95
- Distance
- 78.8 light years
- Coordinates (J2000)
- RA 200.985° · Dec 54.920°
- Catalogue
- HYG 118887 · HD 116657
A symbolic commemorative gift: neither the signature nor the chosen name implies ownership of the star or recognition by the IAU.
Other stars in Ursa Major
Ursa Major has 124 stars in Stelvia's catalogue. Here are a few of them.
- AliothEpsilon Ursae Majoris1.76
- DubheAlpha Ursae Majoris1.81
- AlkaidEta Ursae Majoris1.85
- 23 Ursae Majoris3.65
- TaiyangshouChi Ursae Majoris3.69
- Upsilon Ursae Majoris3.78
- Alcor3.99
- Alula AustralisXi Ursae Majoris4.33