Zeta Canis Majoris (ζ CMa, ζ Canis Majoris) is a spectroscopic binary in the constellation Canis Major. It has the traditional name Furud or Phurud, from the Arabic ألفرد al-furud meaning the bright single ones or, perhaps by a transcriber's error, from Al Ḳurūd (ألقرد - al-qird), the Apes, or Al Agribah (أل أغربة), the Raven by Al Sufi, referring to the surrounding small stars with some of those of Columba (ζ CMa, λ CMa, γ Col, δ Col, θ Col, κ Col, λ Col, μ Col and ξ Col). The Bayer designation Zeta Canis Majoris was assigned by German astronomer Johann Bayer in 1603.
This star system has an apparent visual magnitude of +3.0, making it one of the brighter stars in the constellation and hence readily visible to the naked eye. Parallax measurements from the Hipparcos mission yield a distance estimate of around 362 ly (111 pc) from Earth. This is a single-lined spectroscopic binary system, which means that the pair have not been individually resolved with a telescope, but the gravitational perturbations of an unseen astrometric companion can be discerned by shifts in the spectrum of the primary caused by the Doppler effect. The pair orbit around their common center of mass once every 675 days with an eccentricity of 0.57.
The primary component is a large star with nearly four times the Sun's radius and almost eight times the mass of the Sun. It has a stellar classification of B2.5 V, which means it is a B-type main sequence star that is generating energy through the nuclear fusion of hydrogen at its core. It is emitting 3,603 times the luminosity of the Sun and is a suspected Beta Cephei variable. This energy is being radiated from its outer envelope at an effective temperature of about 18,700 K, giving it the blue-white hue of a B-type star. It is relatively young for a star, with an estimated age of 32 million years.