Theta Canis Majoris (θ Canis Majoris) is a solitary, orange-hued star near the northern edge of the constellation Canis Major, forming the nose of the "dog". The star is visible to the naked eye with an apparent visual magnitude of 4.08. Based upon an annual parallax shift of 12.07 mas as seen from Earth, it is located about 270 light years from the Sun. The star is moving away from Earth with a radial velocity of +96.2 km/s.
This is an old, evolved K-type giant star with a stellar classification of K4 III. Its mass is uncertain, and may be either 1.5 or around 0.9 times the Sun's mass. It is either 7.9 or 8.7 billion years old (assuming as the mass) and has expanded to 33 times the Sun's size. The star is radiating 305 times the Sun's luminosity from its photosphere at an effective temperature of 4,200 K.