Nu<sup>1</sup> Canis Majoris is a binary star in the constellation Canis Major. Its name is a Bayer designation that is Latinized from ý<sup>1</sup> Canis Majoris, and abbreviated Nu<sup>1</sup> CMa or ý<sup>1</sup> CMa. This system is visible to the naked eye as a point of light with an apparent visual magnitude of 5.7. Based on parallax shift of as seen from Earth orbit, this system is approximately 264 light years from the Sun. It is drifting further away with a line of sight velocity of +26 km/s.
As of 2011, the pair had an angular separation of 17.29 arc seconds along a position angle of 264.2ð. The yellow hued magnitude 5.87 primary, component A, is an evolved G-type giant star with a stellar classification of G8 III. It is an estimated 3 billion years old and has 1.4 times the mass of the Sun. Having exhausted the supply of hydrogen at its core, it has expanded to 7 times the Sun's radius and is radiating 8 times the luminosity of the Sun from its photosphere at an effective temperature of 6,091 K.
The magnitude 7.61 companion, component B, is a yellow-white hued F-type main sequence/subgiant hybrid with a class of F3 IV-V.