Alpha Leonis


Distance (Light Years) 77.5 ± 1.5
Apparent Magnitude 1.36
Color (B-V)-0.11

Names For This Star

Regulus is Latin and means "The Little King". According to Allen the name reflects a common belief that the star ruled the affairs of heaven. Rex is another Latin name for the star, meaning "The King."

A further name for the star is the LatinCor Leonis, meaning "The Heart of the Lion." This name reflects the position of Regulus in the figure of the Lion as it is usually visualized.

Other names for the star are Al Kalb al Asad or Kabeleced. These names are derived from the Arabic name Al Kalb al Asad meaning nothing more than "The Heart of the Lion."

Description of the Star

Regulus is a hot, blue B7V main sequence star having a luminosity about 140 times that of the sun and about 3.4 times the diameter. The spectral type implies an effective temperature of 13,000 K and a diameter about 3 times that of the sun.

This star is in fact the A component of a multiple star system. The B and C components are a close binary pair revolving together with a separation of 4.2 arc sec from A. This corresponds to a separation of about 100 AU, that is, two and a half times the distance between the sun and Pluto. The period is 2000 years.

Regulus B is an orange K1V main sequence star having a Apparent Magnitude of 8.13. This star has slightly more than 1/4 of the luminosity of the sun, 70% of the sun's mass, and 80% of the sun's radius.

Regulus C is a 13th magnitude dwarf having a luminosity of 1/330 of that of the sun.

Other Designations For This Star


32 Leonis

Hipparcos Identifier (HIP Number)


Harvard Revised (HR Number)


Henry Draper Catalog (HD Number)


Bonner Durchmusterung (BD Number)

BD+12 2149
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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