Cosmic Scale
Antares
Red supergiant · 550 light-years
How big is Antares?
Antares is about 9.5 × 10⁸ km across.
See Antares in 3D, at true scale
Antares is the red heart of Scorpius, a supergiant so large that if it replaced the Sun it would swallow the orbit of Mars. Its name means 'rival of Mars', for its similar colour.
At a glance
| Diameter | 9.5 × 10⁸ km |
|---|---|
| Mass | 2.69 × 10³¹ kg |
| Diameter compared with Earth | 74,300 × Earth |
| Distance | 550 light-years |
| Surface | 3,660 K |
| Brightness | 75,000 Suns |
| Companion | A hot blue star, Antares B |
Good to know
- It is losing mass so fast that it is surrounded by a glowing nebula of its own gas.
- Its outer layers are so thin that in places the 'surface' is less dense than a laboratory vacuum.
- It will explode as a supernova, probably within the next million years.
- Next smaller: Rho Cassiopeiae · 8.8 × 10⁸ km
- Next larger: Betelgeuse · 1.1 × 10⁹ km