Mekbuda (Zeta Geminorum)

Position of Zeta Geminorum

Mekbuda (Zeta Geminorum) is one of the sky's few easily visible Cepheid variables. Lying in the constellation Gemini, Mekbuda changes from magnitude 3.7 to 4.1 and back every 10.2 days. Its Arabic name refers to a "lion's paw," a larger Arabic figure that overlaid our modern constellations, and at one time may have more referred to one of Gemini's luminaries, Castor or Pollux. Mekbuda, positioned just southwest of brighter Wasat (Delta Geminorum), shines yellow-white and has a temperature similar to that of the Sun. There, however, the similarity ends because Mekbuda is an aging supergiant. Through a small telescope, it appears to have a faint companion one arc-minute arc away, but this is a line-of-sight coincidence. The bright star itself, however, does seem to have a true faint companion that can't be resolved by telescope.


visual magnitude 3.7 to 4.1
absolute magnitude -3.77
luminosity 3,000 Lsun
radius 60 Rsun
distance 1,170 light-years
position R.A. 07h 04m 06.5s,
Dec. +20° 34' 13"