Alpha Ophiuchi


Distance (Light Years) 46.7 ± 0.6
Apparent Magnitude 2.08
Color (B-V)0.15

Names For This Star

Rasalhague, alternatively Ras Alhague, derives from the Arabic name for this star, Al Ras al Hawwa, "The Head of the Serpent-Charmer."

Description of the Star

Rasalhague is a hot, white A5III giant having 26 times the luminosity of the sun, and 2.4 times the diameter.

Rasalhague has an unseen companion revolving in an orbit at an angular separation of 0.065 arc sec from the primary, that is, just under 1 AU from the central star. The period of the orbit is 8.5 year. According to Burnham the masses would be 2.4 solar masses and 0.6 solar masses for the giant and the companion respectively.

Other Designations For This Star


55 Ophiuchi

Hipparcos Identifier (HIP Number)


Harvard Revised (HR Number)


Henry Draper Catalog (HD Number)


Bonner Durchmusterung (BD Number)

BD+12 3252
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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