Luminosity

luminosity, in astronomy, the amount of light emitted by an object in a unit of time. The luminosity of the Sun is 3.846 × 10²⁶ watts (or 3.846 × 10³³ ergs per second). Luminosity is an absolute measure of radiant power; that is, its value is independent of an observer’s distance from an object. Astronomers usually refer to the luminosity of an object in terms of solar luminosities, with one solar luminosity being equal to the luminosity of the Sun. The most luminous stars emit several million solar luminosities. The most luminous supernovae shine with 10¹⁷ solar luminosities. The dim brown dwarfs have luminosities a few millionths that of the Sun.