giant · A0III
Thuban
Thuban is a blue-white giant (spectral type A0III) about 300 light-years away. With an apparent magnitude of 3.67 it is easy to see with the naked eye under a dark sky.
About 4,700 years ago, in the age of the pyramids, it was the pole star.
Its light output is roughly 250 times that of the Sun (a rough estimate in visible light, calculated from brightness and distance).
From Germany (52° N) it never sets: it stays above the horizon all year.
Key facts
- Distance
- ≈ 300 light-years
- Spectral type
- A0III (giant)
- Colour
- Blue-white
- Apparent magnitude
- 3.67 mag
- Luminosity
- ≈ 250 × Sun
- Position
- Right ascension 14h 4m, declination 64.4°
More well-known stars
Data: Hipparcos / HYG catalogue (CC BY-SA 4.0). Luminosity and visibility are calculated estimates.