Cosmic Scale
Mu Cephei
Red supergiant · 3,000 light-years
How big is Mu Cephei?
Mu Cephei is about 1.4 × 10⁹ km across.
See Mu Cephei in 3D, at true scale
Mu Cephei is a deep red supergiant that William Herschel called 'a most beautiful garnet colour' — hence its nickname, the Garnet Star. It is one of the largest and most luminous stars in the Milky Way.
At a glance
| Diameter | 1.4 × 10⁹ km |
|---|---|
| Mass | 3.82 × 10³¹ kg |
| Diameter compared with Earth | 106,000 × Earth |
| Distance | About 3,000 light-years |
| Surface | 3,750 K |
| Brightness | Around 300,000 Suns |
| Radius | Around 970 Suns |
Good to know
- Its red colour comes from being cool and from dust the star itself has made and blown away.
- It varies irregularly over years as it pulsates.
- It has already fused helium into carbon and is close to the end of its life.