Luminous objects are responsible for our vision.
In complete darkness we cannot see/distinguish the different objects around us.
Human eye perceives the light reflecting from different objects to cause the sensation of vision.
In order to reflect (bounce back, come back) from different objects, we must make the light to fall on the objects.
Light is generated/emitted/produced/comes from only luminous objects. Thus luminous objects are responsible for our vision.
Example - Example: Lighted candle, torch bulb, the sun and stars.
In order to emit light, the object must have its own source of energy. A torch shines because of the chemical energy stored in its batteries, whereas all stars shine using energy created by nuclear fusion
Sun also emits light as a result of fusion of Hydrogen atoms. Hence they are considered as Luminous objects.