What is a planetary nebula quizlet?

A planetary nebula is a type of nebula that represents the final stage of evolution for low-mass stars (between 0.8 and 8 times the mass of the Sun). It is created when the outer layers of a dying star expand and are expelled into space, forming a glowing shell of gas and dust. The core of the star left behind, known as a white dwarf, illuminates the nebula.

Here are some key points about planetary nebulae that you can find on Quizlet:

1. Planetary nebulae have a round or elliptical shape, resembling a planet when viewed through early telescopes. However, they have nothing to do with planets themselves.

2. The colors observed in a planetary nebula are caused by the emission and absorption of light by different elements present in the shell, such as hydrogen, helium, oxygen, and nitrogen.

3. Planetary nebulae typically have a diameter of a few light-years, expanding at speeds of about 10 to 25 kilometers per second.

4. The size and shape of planetary nebulae vary greatly. Some appear as symmetric shells, while others exhibit more complex structures, such as bipolar or quadrupolar lobes.

5. These nebulae can last for tens of thousands of years before dispersing into the interstellar medium.

6. The first planetary nebula, the Dumbbell Nebula (M27), was discovered by Charles Messier in 1764.

7. Planetary nebulae play a crucial role in recycling heavy elements like carbon and nitrogen back into the universe, enriching future generations of stars and planetary systems.

By studying planetary nebulae, astronomers can gain insights into the late stages of stellar evolution, the formation of white dwarfs, and the overall chemical enrichment of galaxies.