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 a evolved K-type giant star with a stellar classification of K4 III. Theta Canis Majoris is 5% less massive than the Sun, but has expanded to 33 times the Sun's size. This old star, around ten billion years old, is over two times older than the Solar System. It irradiates 305 times the Sun's luminosity from its expanded photosphere at an effective temperature of 4,200 K. This temperature gives it the cool orange hue of a K-type star.