Arcturus

Arcturus, the alpha star of the constellation Boötes, the Herdsman, is the brightest star visible in the summer months.  Arcturus offers a glimpse of our Sun’s future.  Already a Red Giant it is 24 times the size of our Sun.  Eventually, it will exhaust its fuel supply and become a white dwarf at the end of its life. Our Sun will evolve in a similar manner as it grows in size absorbing Mercury, Venus and the Earth before shrinking down to a white dwarf.

Arcturus is easy to find … just remember the phrase “Follow the arc to Arcturus.” The arc refers to the curving handle of the Big Dipper. Find the Big Dipper’s handle, follow its curve (away from the bowl of the dipper) and the first bright star you come to is Arcturus.

A bit of trivia … Arcturus is 37 light years away from Earth, although in the early 1930s astronomers estimated Arcturus’ distance at 40 light years.  The star became famous when its light helped open the 1933 Chicago world’s fair.  The previous time Chicago held the world’s fair was 40 years earlier in 1893.

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Arcturus Overview:

  • Constellation Boötes
  • Alpha (α) 14h16m, +19°10′
  • Type Giant star
  • Magnitude -0.04
  • Luminosity  215 Suns
  • Spectral Type K1III
  • Distance 37 light years

Boötes (bo-OH-teez) Constellation … The Herdsman

The distinctive kite-shape of Boötes lies eastward of Ursa Major, its base marketed by the brilliant red of Arcturus.  It is said to be the herdsman, Boötes, forever driving away the bears Ursa Major and Minor. The origin of the name Boötes is not certain, but it probably comes from a Greek word meaning ‘noisy’ or ‘clamorous’, referring to the herdsman shouts to his animals.

Astronomy 101