Arcturus Star Facts
Arcturus star
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.

Arcturus compared to the sun
Our sun compared in size to the orange giant star Arcturus.
Arcturus Radius
Arcturus 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 Mass
Arcturus is estimated to have a mass of around 1.1 times that of the sun.
Arcturus Temperature
Arcturus 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 Statistics

Also Known As: Alpha Boötes

Distance From Earth: 37 light years

Constellation: Boötes

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