An emission nebula is a type of interstellar cloud primarily composed of ionized gas, particularly hydrogen, which emits light of various wavelengths. This emission occurs as a result of energetic ultraviolet radiation, typically from nearby hot, young stars. The high-energy photons from these stars ionize the surrounding hydrogen gas, causing the gas atoms to recombine and release energy in the form of light. The most prominent spectral lines in this emitted light are the red H-alpha emission lines, originating from hydrogen. These nebulae are often seen in star-forming regions, where the intense radiation from newborn stars both illuminates and interacts with the surrounding gas and dust, creating a luminous, glowing cloud. The study of emission nebulae provides significant insights into stellar formation, ionization processes, and the composition of interstellar matter.
- Composed primarily of ionized hydrogen, that makes it glow
- Emit their own light due to the excitation of hydrogen atoms by ultraviolet light from nearby hot, young stars.
- Often appear in vibrant colors like red and pink, due to the H-alpha emission line from hydrogen.
- Orion Nebula (M42): Located in the Orion constellation, it's one of the brightest nebulae visible to the naked eye.
- Eagle Nebula (M16): Known for the "Pillars of Creation," where new stars are forming.
