Alpha Crucis (star)

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α1 Crucis (A + Ab)
Spectral B0.5 IV
Type Subgiant
Multiple Binary
Luminosity 25,000 LSol LSol
Lum Rank 45th
Absolute magnitude −4.19
Mag Terra 1.40 (23rd)
Temperature 28,000 K° K
Mass 14 MSol MSol
Companion α1 Crucis Ab (Mass = 10Sol)


α2 Crucis (B)
Spectral B1 V
Type Main Sequence
Multiple B-Companion
Luminosity 16,000 LSol LSol
Absolute magnitude
Mag Terra 2.09
Temperature 26,000 K° K


α3 Crucis (C)
Spectral B4 IV
Type Subgiant
Multiple C-Companion
Luminosity LSol
Absolute magnitude
Mag Terra 2.09
Temperature ° K


Alpha Crucis or Acrux is a quadruple star consisting of the binary A-components α1 [A] (B0.5 IV) and α1 [Ab] (spectrum unknown), the B-component α2 (B1 V), and the C-component α3 (B4 IV):

  • α1 [A] (B0.5 IV)
  • α1 [Ab] (spectrum unknown)
  • α2 [B] (B1 V)
  • α3 [C] (B4 IV)

Description (Specifications)

Only two components are visually distinguishable from Terra, α1 and α2, separated by 4 arcseconds. α1 is magnitude 1.40 and α2 is magnitude 2.09, both hot class B (almost class O) stars, with surface temperatures of about 28,000 and 26,000 K respectively. Their luminosities are 25,000 and 16,000 times that of the Sun. α1 and α2 orbit over such a long period that motion is only barely seen. From their minimum separation of 430AU, the period is at least 1,500 years, and may be much longer.

α1 is itself a spectroscopic binary star, with its components thought to be around 14 and 10 times the mass of the Sun and orbiting in only 76 days at a separation of about one astronomical unit. The masses of α2 and the brighter component of α1 suggest that the stars will someday explode as supernovae. The fainter component of α1 may survive to become a massive white dwarf.

Another class-B4 subgiant, Alpha Crucis C or α3 Crucis, lies 90 arcseconds away from triple Acrux and shares Acrux's motion through space, suggesting it may be gravitationally bound to Acrux. It is therefore generally assumed to be physically associated with Acrux.

  • Alpha Crucis is the 13th brightest star as seen from Terra, individually they are the 23rd (α1) and 57th (α2) brightest star. It is the 45th brightest star in the galaxy, and one of the brightest in Charted Space. None of the Alpha Crucis stars are significantly large.
  • The Alpha Crucis star system is approximately 99pc from Terra, and is located in a Trailing direction from Terra at bearing 300.13o Galactic Longitude and -00.4o South Galactic Latitude.

History & Background (Dossier)

No Information currently available.


References & Contributors (Sources)

This article has metadata.


This list of sources was used by the Traveller Wiki Editorial Team and individual contributors to compose this article. Copyrighted material is used under license from Far Future Enterprises or by permission of the author. The page history lists all of the contributions.
Smallwikipedialogo.png This page uses content from Wikipedia. The original article was at Alpha_Crucis. The list of authors can be seen in the page history. The text of Wikipedia is available under the Commons Attribution-ShareAlike 3.0 Unported License.
  • External Link: SIMBAD @ University of Strasbourg: [2]
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