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Arcturus: Orange Giant

What's in a Name: Greek for "Bearkeeper". The bear is the constellation Ursa Major (the Great Bear).
Claim to Fame: 4th brightest star in the sky. The reddish light of Arcturus striking a photoelectric cell marked the beginning of the 1934 Chicago World's Fair.
Type of Star: Orange Giant (K2 III Spectral Class), surface temperature 4400K. Fusing helium to carbon and oxygen in its core.
How Far Away: 37 light years away
How Big: 18 times larger than the sun, 4 times the sun's mass
How Bright: 105 times the sun's luminosity (Mv=-0.3)
Where to View: Brightest star in the constellation Bootes, the Herdsman (Star Map).
When to View: April through August from Northern middle latitudes
Last modified April 28, 2005 by Travis Metcalfe.

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The Summer 2010 issue of The Earth Scientist, available in our online store, includes articles on rivers and snow, classroom planetariums, satellites and oceanography, hands-on astronomy, and global warming.

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