Arcturus Star Facts
A telescopic view of Arcturus which is the fourth brightest star in the night sky.
- Arcturus is an orange giant star approximately 37 light years from Earth.
- It is part of the Boötes constellation, pronounced boo-oh-tes, meaning herdsmen.
- Arcturus is visible to the naked eye in both the northern and southern hemispheres.
- Arcturus was possibly similar to our sun but has now passed the main sequence period of its lifespan.
- Instead of fusing hydrogen like our sun, Arctutus is now fusing helium in its core, causing it to expand.
- Arcturus is part of the Arcturus Stream, a group of ancient stars which move at a different angle and at a greater speed than other stars in our galaxy.
- The Arcturus Stream is thought to be the remnants of a dwarf galaxy that collided with the Milky Way.
- In around a million years Arcturus will be so far from Earth it will no longer be visible to the naked eye.
- Arcturus is derived from the ancient Greek words arktos, meaning bear, and ouros, meaning guardian.
Our sun compared in size to the orange giant star Arcturus.
Arcturus RadiusArcturus is an orange giant star with a radius of around 11 million miles (18 million km), which is around 26 times the size of the sun.
Arcturus MassArcturus is estimated to have a mass of around 1.1 times that of the sun.
Arcturus TemperatureArcturus is estimated to have surface temperatures of around 4000C (7200F), around 73% as hot as the sun.
Arcturus Luminosity (energy emitted)Due to its large size the star's luminosity is between 100 to 200 times greater than that of our sun.
Arcturus StatisticsAlso Known As: Alpha Boötes
Distance From Earth: 37 light years
Star Type: Orange Giant - K Class
Mass: 110% of the Sun
Luminosity: 100 to 200 times the Sun
Diameter: Approx 22 million miles (36 million km) - 26 times the Sun
Temperature: Approx 4000C (7200F)
Age: Approx 10 billion years old
Rotation Period: 2 years