luminosity

Luminosity refers to the total amount of light energy emitted by a star or other celestial object per unit of time. It is an intrinsic property, meaning it does not depend on distance from the observer. Luminosity is often measured in watts, similar to how we measure the output of light bulbs. A star’s luminosity can provide important information about its size, temperature, and stage in its life cycle. For example, a very luminous star is usually much larger and hotter than a dimmer star. Understanding luminosity helps astronomers study and categorize stars and galaxies.