(nearest star system)
Alpha Centauri (Rigil Kentaurus) is the nearest
star system to the Earth beyond the Sun.
The entire system has three stars:
the two larger form a binary star:
Alpha Centauri A, a G2 V-type star with absolute magnitude 4.38
and Alpha Centauri B a K1 V-type star with absolute magnitude 5.71.
8.30. They orbit in about 80 years and without a telescope,
they have the appearance of a single star.
The third star is Alpha Centauri C or Proxima Centauri,
a red dwarf of type M6 Ve and an absolute magnitude of 15.6.
It is currently the closest of the three to Earth,
orbiting the binary system about once every half million years,
currently about a fifth of a light-year from them
and about 2 degrees from them across the Earth's celestial sphere.
It has an extra-solar planet of interest, Proxima B,
that appears to be in its habitable zone.
Characteristics (Alpha Centauri A):
(star,nearby star,binary star,bright star,exoplanets)
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absolute magnitude (M)
apparent magnitude (m)
astronomical unit (AU)
globular cluster (GC)