Cosmic Scale
Rho Cassiopeiae
Yellow hypergiant · About 3,400 light-years
How big is Rho Cassiopeiae?
Rho Cassiopeiae is about 8.8 × 10⁸ km across.
See Rho Cassiopeiae in 3D, at true scale
Rho Cassiopeiae is a yellow hypergiant, one of the rarest kinds of star, about half a million times brighter than the Sun; in the Sun's place it would reach into the asteroid belt. It is visible to the naked eye despite being thousands of light-years away.
At a glance
| Diameter | 8.8 × 10⁸ km |
|---|---|
| Mass | 7.96 × 10³¹ kg |
| Diameter compared with Earth | 69,400 × Earth |
| Distance | About 3,400 light-years |
| Radius | Around 600 Suns |
| Brightness | About 500,000 Suns |
| Type | Yellow hypergiant |
Good to know
- In 2000 it shed about 3% of the Sun's mass in a single outburst.
- Only a handful of yellow hypergiants are known in the whole Milky Way.
- It is unstable and pulsates, dimming and brightening irregularly.
- Next smaller: Pistol Star · 4.3 × 10⁸ km
- Next larger: Antares · 9.5 × 10⁸ km