半人馬座ξ2

半人馬座Xi2 （ξ2 Cen, ξ2 Centauri）是在南天人馬座的三星系統，這較寬的光學雙星視星等為裸眼可見的+4.30等，略比半人馬座ξ1A型主序星暗（+4.83等），年週視差6.98mas，距離太陽大約470光年。在這樣的距離，恆星會因為中間的星際塵埃造成消光，而使視星等減弱0.32等

This system was discovered to be a single-lined spectroscopic binary in 1910 by American astronomer Joseph Haines Moore. The pair, component A, orbit each other with a period of 7.6497 days and an eccentricity of 0.35. The primary is a B-type star with a stellar classification of B1.5 V or B2 IV, depending on the source. This indicates it may be a main sequence star or a more evolved subgiant star. It has about 8.1 times the mass of the Sun and radiates 1,702 times the solar luminosity from its outer atmosphere at an effective temperature of 20,790 K. It is a hybrid pulsator and shows spacings in both g and p modes.

A third star, component B, is a magnitude 9.38 F-type main sequence star with a classification of F7 V. It has 1.25 times the mass of the Sun and radiates 2.4 times the solar luminosity at an effective temperature of 6,194 K. It lies at an angular separation of 25.1 arc seconds from the inner pair. They share a common proper motion, indicating they may be gravitationally bound with an orbital period of around 41,000 years.

The system has a peculiar velocity of . It belongs to the Scorpius–Centaurus association and appears to be a member of the Gould's Belt.

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人馬座
Centauri, Xi1
波恩天體
113791
064004
4942