Arcturus (Alpha Bootis)
Arcturus (Alpha Bootis) is the brightest star in the constellation Bo÷tes and in the entire northern hemisphere, and the fourth brightest in the sky;
its Greek name means the "Bear Watcher," in reference to the star's apparent
pursuit of Ursa Major around the pole. An orange
subgiant K star, Arcturus has a velocity somewhat
higher than that of other bright stars, and comes from an older population
of the Galaxy. Consistent with this, it is rather metal-poor with only about
one-fifth as much iron relative to hydrogen as is found in the Sun. It is
probably at the stage of fusing helium to carbon in its core.
Arcturus became famous when its light was used to open the 1933 World's
Fair in Chicago – this light having started its journey at about the
time of the previous Chicago fair in 1893. Arcturus was one of the first
stars to have its proper motion measured.
It is the scene for David Lindsay's classic
fantasy A Voyage to Arcturus.
||R.A. 14h 15m 39.7s,
Dec. +19░ 10' 57"
• brightest stars