Cosmic Scale
UY Scuti
Red supergiant · 5,900 light-years
How big is UY Scuti?
UY Scuti is about 1.3 × 10⁹ km across.
See UY Scuti in 3D, at true scale
UY Scuti is a pulsating red supergiant in the constellation Scutum, and for years it topped the lists of the largest known stars. Later distance measurements make it less certain, which is typical of these enormous, poorly-defined stars.
At a glance
| Diameter | 1.3 × 10⁹ km |
|---|---|
| Mass | 1.39 × 10³¹ kg |
| Diameter compared with Earth | 99,300 × Earth |
| Distance | About 5,900 light-years |
| Surface | 3,365 K |
| Radius | Around 900 Suns |
| Variability | Pulsates over ~740 days |
Good to know
- Its edge is not sharp: the star fades gradually into its own wind, so its 'size' depends on where you stop measuring.
- Placed where the Sun is, its surface would reach past the asteroid belt.
- It loses about the mass of Earth every few years to its stellar wind.
- Next smaller: Betelgeuse · 1.1 × 10⁹ km
- Next larger: Mu Cephei · 1.4 × 10⁹ km