A planetary nebula is a glowing shell of gas and dust ejected from a star during the late stages of its evolution, particularly when it has exhausted its nuclear fuel and expelled its outer layers. This process usually occurs in stars that are similar in size to our Sun and marks the transition from the red giant phase to the final stage, where the core remains as a white dwarf. The vibrant colors and structures observed in planetary nebulae are due to ionized gas that emits light as it interacts with ultraviolet radiation from the remaining hot core.
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