Stars · Star in Boötes
Star
Arcturus
The brightest star in the northern sky: an orange giant, older than the Sun, whose light once switched on a World’s Fair.
- Constellation
- Boötes
- Designation
- α Boötis
- Apparent magnitude
- -0.05 · 4th brightest star in the night sky
- Spectral class
- K2IIIp
- Distance
- 36.7 light-years
- Position (J2000)
- RA 14h 16m · Dec +19° 11′
An orange giant, around 4,900 K, like Aldebaran. About 420× brighter than the faintest star the eye can see. The light you are seeing left in 1989.
Look for
Find it by following the Big Dipper’s handle: “arc to Arcturus”. Its colour is a clear soft orange next to white Spica.
History
In 1933 its light, focused onto a photocell, turned on the lights of Chicago’s Century of Progress fair. The light was thought to have left in 1893, the year of the city’s last fair.
Science
It moves through the galaxy along a steep path unlike the Sun’s; it may be a visitor, taken in with a small galaxy the Milky Way swallowed.