Beta Centauri


Distance (Light Years) 525 ± 47
Apparent Magnitude 0.61
Color (B-V)-0.23

Names For This Star

Hadar is an Arabic word meaning "Ground."

Another name for the star is Agena. According to a note in Allen, this name appears to be a compound of the letter "A" for alpha and "gena" meaning knee. (See the note on p. 154 of the 1963 Dover.) The root of the name would presumably be Latin. However, the only meaning that I have been able to find for the word "gena" is "cheek" rather than "knee".

Description of the Star

Hadar is a blue, hot B1III giant star, maybe 13,000 times as luminous as the sun. There is a companion star lying at an angular separation of 0.871 sec of arc, that is, at a projected distance of 140 AU.

The spectrum of the star seems to indicate further companions revolving with respective periods of 3.7 hours and 352 days.

Other Designations For This Star


Hipparcos Identifier (HIP Number)


Harvard Revised (HR Number)


Henry Draper Catalog (HD Number)


Bonner Durchmusterung (BD Number)

CP-59 5365
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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