Red supergiant · variable star
UY Scuti
UY Scuti is a red supergiant in the constellation Scutum, about 9,500 light-years away. Its radius is estimated at roughly 900 to 1,200 solar radii. Placed where the Sun is, its surface would reach about as far as Jupiter's orbit.
The star pulsates and changes brightness irregularly. Size figures are uncertain because the distance and surface of such a bloated, dust-shrouded star are hard to measure. UY Scuti was long considered the largest known star; other candidates such as Stephenson 2-18 are now thought to be larger.
Despite its diameter it is not especially massive (about 7 to 10 solar masses): its envelope is extremely thin. It will end as a supernova on astronomical timescales.
Key facts
- Distance
- ≈ 9,500 light-years
- Star radius
- ≈ 900–1,200 solar radii (uncertain)
- Surface temp.
- ≈ 3.100 °C
- Star mass
- ≈ 7–10 solar masses
- Brightness
- variable, ≈ 8–11 mag
Images
More famous objects
Images: NASA, ESA, ESO, Event Horizon Telescope, Wikimedia Commons. Artist's impressions are labelled as such. Figures from published research, rounded.