Final answer:
A planetary nebula is not the disk of matter around a star that will eventually form a planetary system.
Step-by-step explanation:
A planetary nebula is not the disk of matter around a star that will eventually form a planetary system.
A planetary nebula is actually a glowing shell of gas and dust that is ejected by a star in the late stages of its evolution. This ejection happens when the star has exhausted its nuclear fuel and its outer layers are expelled into space, forming a beautiful nebula with a variety of shapes and structures.
On the other hand, a disk of matter around a star that can potentially form a planetary system is called a protoplanetary disk or a circumstellar disk. These disks are found around young stars and are composed of gas, dust, and debris. Over time, the material in these disks can come together through gravity to form planets, moons, asteroids, and other celestial bodies.