Rigel
Star · Blue supergiant
Rigel is a blue supergiant marking Orion’s foot. It is much hotter than our Sun and pours out tens of thousands of times more light. Blue supergiants live fast and die young.
- 860 light-years awayEven light – the fastest thing there is – needs 860 years to get here.
- ~12,000 °CTemperature
- OrionConstellation
Take a closer look
A blue giant furnace
Rigel is about 20 times heavier than the Sun and roughly 75 times wider. Being so big and hot, it burns through its fuel at a furious rate. It is only about 8 million years old, but it is already running low – a star like the Sun lasts about a thousand times longer.
Lighting up a witch
Rigel is so bright that it lights up a faint cloud of dust far from it, nicknamed the Witch Head Nebula because its shape looks like a witch’s face in profile. The dust reflects Rigel’s blue light, a bit like fog glowing around a car’s headlights.
Orion’s brightest star
Astronomers often label each constellation’s brightest star “Alpha”. In Orion, that label went to Betelgeuse – yet Rigel, the “Beta” star, is usually the brighter of the two. Before it dies, Rigel will probably swell and cool into a red supergiant, much like Betelgeuse.
How we found out
- Ancient times
Its name comes from the Arabic word for “foot”.
- 1831
Friedrich Georg Wilhelm von Struve measures a faint companion star close to Rigel.
Why are hot stars blue and cooler stars red?
Same reason a heated metal rod glows red, then orange, then white-blue as it gets hotter. Hotter things give off light of shorter wavelengths.
See it yourself
The bright blue-white star at Orion’s lower-right foot (from the Northern Hemisphere).
From the encyclopedia
Read the full article on Wikipedia ↗Got it?
Mark Rigel as explored to earn 10 XP.