It owes its brilliance to being one of the Sun's closest neighbours at 8.7 light years away, and as well, is about eight times more luminous than the Sun. Sirius has a white dwarf companion that orbits it every 50 years. Closest approach was in 1993, while the widest separation will be in 2022. The white dwarf will not be visible to most backyard observers, however, until the early years of next century. Even then it remains difficult to see because of the glare of Sirius.
White dwarfs are therefore exceptionally dense bodies.
A teaspoonful of material would have a mass of thousands of kilograms or over 100,000 times that of water. Over thousands of millions of years they slowly cool off and fade. It is a beautiful object in binoculars and small telescopes, containing some delicate pairs and triplets, with a fine orange star near the centre. It lies about 2500 light years away. Small telescopes and binoculars show about 40 stars in the cluster.