spherical shape
central star remnant
Responses
dark area
spherical shape
central star remnant
diffuse edges
central star remnant
1) Spherical shape: Planetary nebulas typically have a round or spherical shape.
2) Central star remnant: Planetary nebulas are formed from the outer layers of a dying star, leaving behind a central star remnant.
1. Spherical shape: Planetary nebulae often have a round or roughly spherical shape. This is due to the expansion of material released from the dying star into space, creating an expanding shell of gas and dust.
2. Central star remnant: Planetary nebulae are formed when a low to medium mass star reaches the end stages of its life. The central star, which is the remnant of the dying star, is often visible within the nebula. This star is usually hot and emits intense ultraviolet radiation, which causes the surrounding gas to glow.
Therefore, the correct answers would be:
- Spherical shape.
- Central star remnant.