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Become a nitrogen atom in the nitrogen cycle in our Traveling Nitrogen Classroom Activity Kit/Game. See all our games, activity kits and classroom activities.

Alpha Centauri - The Sun's Twin


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What's in a Name: Sometimes called Rigel Kentaurus meaning "foot of the Centaur" in Arabic.
Claim to Fame: Member of the triple star system closest to our sun. 3rd brightest star in the sky (apparent visual magnitude = -0.3).
Type of Star: Yellow-Orange Main Sequence star (G2 V Spectral Class).
How Far Away: 4.3 light years away
How Big: About the same size as the sun
How Bright: 40% brighter than the sun. Absolute visible magnitude Mv = +4.4
Where to View: Located in the constellation Centaurus, the Centaur (Star Map)
When to View: Centaurus is never in the sky viewed from middle northern latitudes (around 40 degrees). As you travel south on the Earth's surface and pass below the equator, you will definitely see it from time to time.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA