Sirius in fiction below)—and even if such were eventually discovered, with an estimated age of 230 million years the system is too young to have fostered the development of life or a complex biosphere. Sirius AB is the alpha star of the constellation Canis Major (the great dog, sometimes styled as Orion's hunting dog), whence its cognomen "the dog star". The most commonly used proper name of this star comes through the Latin "Sirius", from the Greek Σείριος ("Seirios", "glowing" or "scorcher"). The ancient Greeks observed that the appearance of Sirius heralded the hot and dry "dog days" of summer, and feared that
Sirius approximately 296,000 years. Sirius is a binary star system consisting of two white stars orbiting each other with a separation of about 20 AU (roughly the distance between the Sun and Uranus) and a period of 50.1 years. The brighter component, termed Sirius A, is a main-sequence star of spectral type early A, with an estimated surface temperature of 9,940 K. Its companion, Sirius B, is a star that has already evolved off the main sequence and become a white dwarf. Currently 10,000 times less luminous in the visual spectrum, Sirius B was once the more massive of the two.