Kakkab (Alpha Lupi)

Image credit: ESO Online Digitized Sky Survey

The brightest star in the constellation Lupus; its (rarely used) ancient name comes from the phrase Kakkab Su-gub Gud-Elim meaning "the Star Left of the Horned Bull."

Kakkab is a hot giant B star belonging to the Upper Centaurus-Lupus Association (UCL), which in turn is part of a huge collection of O and B stars called the Scorpius-Centaurus Association. From analysis of all its members, UCL lies at an average distance of 450 light-years, which fits well with Kakkab's individually measured distance.

Like many of its spectral type, Kakkab is a Beta Cephei star, a variable that pulsates subtly with multiple periods. With a major oscillation cycle of 0.259847 days (the period really is known to such accuracy), in which it varies by only 0.03 magnitudes (about 3%), Kakkab has one of the longest periods of its class. A secondary pulsation takes 0.236798 days. A 13th magnitude star, just 28" away, may be a genuine companion of Kakkab or may be simply an optical double.

visual magnitude	2.30
absolute magnitude	-3.83
spectral type	B1.5III
luminosity	18,000 L_sun
temperature	21,600 K
mass	10 to 11 M_sun
distance	548 light-years (168 pc)
position	R.A. 14h 41m 55.8s, Dec. -47° 23' 18"

Related category

• NOTABLE STARS

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