Alioth vs Dubhe
The pair differs by one class, Alioth as an A-type star in Ursa Major and Dubhe as an F-type star in Ursa Major. Absolute magnitudes of −1.07 for Dubhe and −0.26 for Alioth put a factor near 2.1 between their true outputs. Distance divides them sharply — 123 light-years to Dubhe against 82.5 for Alioth.
Property comparison
| Property | Alioth | Dubhe |
|---|---|---|
| ชื่อเรียก | 77Eps UMa | 50Alp UMa |
| กลุ่มดาว | Ursa Major | Ursa Major |
| ประเภทสเปกตรัม | Class A — A-type (White) | Class F — F-type (Yellow-White) |
| โชติมาตรปรากฏ | +1.76 | +1.81 |
| โชติมาตรสัมบูรณ์ | -0.26 | -1.07 |
| ระยะทาง | 82.5 ly | 123 ly |
| มวล | N/A | N/A |
| รัศมี | N/A | N/A |
| อุณหภูมิ | N/A | N/A |
| ความส่องสว่าง | N/A | N/A |
Full data for each star: Alioth · Dubhe
Key differences
Key Differences
- ◆ Both are the two brightest stars of the Big Dipper in Ursa Major, but they differ in type and motion.
- ◆ Alioth (Epsilon UMa) is an A-type chemically peculiar variable; Dubhe (Alpha UMa) is a K-type giant.
- ◆ Alioth is a member of the Ursa Major Moving Group; Dubhe is not and moves in the opposite direction.
- ◆ Dubhe forms the 'pointer pair' with Merak that indicates Polaris.
- ◆ Alioth is slightly brighter than Dubhe despite the Alpha/Epsilon designations.