Alpha Virginis


Distance (Light Years) 262 ± 18
Apparent Magnitude 0.98
Color (B-V)-0.23

Names For This Star

Spica is Latin and means "The Ear of Wheat. This name suggests the association of Virgo with the Goddess of the Harvest, Ceres or Demeter. The Latin name Spica Virginis means nothing more than "The Virgin's Ear of Wheat."

An alternative name for the star is Azimech, which derives from the Arabic name Al Simak al A'zal, that is, "The Undefended." This refers to the separation of the star from its neighbors.

According to the The Bright Star Catalog, the name Alaraph has been applied to Spica as well as to Vindemiatrix and to Beta Virginis.

Description of the Star

Spica is a double star system consisting of a blue B1III-IV subgiant or giant in association with a blue B2V main sequence star.

The two stars orbit about their common center of mass with a period of 4.0 days. According to Burnham the two stars are separated by 11 million miles center to center. The orbit is inclined at about 24° to the line of sight, so that the orbit is seen not quite edge on. Nevertheless the stars do eclipse one another, and the brightness of the system varies by about 0.07 magnitudes as one star passes in front of the other.

The giant star is about 7.4 times the diameter of the sun. The dynamics of the orbit indicates that the giant has a mass of 10.9 solar masses, while the smaller star is about 6.8 times the mass of the sun.

The combined luminosity of the two stars is about 2200 times that of the sun with about 80% of the light output coming from the giant star. The giant is a short period variable star of Beta Canis Majoris type with a 4.2 hour period.

Other Designations For This Star


67 Virginis

Hipparcos Identifier (HIP Number)


Harvard Revised (HR Number)


Henry Draper Catalog (HD Number)


Bonner Durchmusterung (BD Number)

BD-10 3672
Smithsonian Astrophysical
Observatory compendium (SAO Number)

Fundamental Katalog (FK5 Number)



Copyright © 1998 - 2010 by Arnold V. Lesikar,
Professor Emeritus
Dept. of Physics, Astronomy, and Engineering Science,
St. Cloud State University,St. Cloud, MN 56301-4498

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