Canis Major
Canis Major is a prominent constellation because of its many bright stars. These include Sirius (Alpha Canis Majoris), the brightest star in the night sky, as well as three other stars above magnitude 2.0. Furthermore, two other stars are thought to have previously outshone all others in the night sky—Adhara (Epsilon Canis Majoris) shone at -3.99 around 4.7 million years ago, and Mirzam (Beta Canis Majoris) peaked at −3.65 around 4.42 million years ago. Another, NR Canis Majoris, will be brightest at magnitude −0.88 in about 2.87 million years' time.
Blue supergiant star
The best known example is Rigel, the brightest star in the constellation of Orion. Its mass is about 20 times that of the Sun, and its luminosity is around 117,000 times greater. Despite their rarity and their short lives they are heavily represented among the stars visible to the naked eye; their immense brightness is more than enough to compensate for their scarcity.