A luminous object is one that can create its own light, powered by an internal energy source. Luminous objects tend to generate heat due to the light they emit.
Any object capable of sustaining its own energy source and light is called a self-luminous object. Stars are examples self-luminous objects, powered by nuclear fusion. This energy source allows them to emit light and radiate heat without relying on light reflections from other sources or external sources of energy.
Objects that are incapable of storing energy and emitting their own light are known as non-luminous objects. These objects become visible when they reflect light from luminous sources.