b. diffuse edges
c. spherical shape
a. dark area
b. diffuse edges
c. spherical shape
d. central star remnant
c. spherical shape
a. stars explode to form nebulae
b. stars are pulled toward nebulae
c. stars form from nebulae
d. nebulae explode to form stars
e. nebulae are found inside stars
f. nebulae form from stars
f. nebulae form from stars
c. stars form from nebulae
f. nebulae form from stars
a. force of a nebula
b. energy of a nebula
c. energy of heat
d. force of gravity
a. its edges do not have clear boundaries
b. it reflects only non-visible radiation
c. its edges have clear boundaries
d. it reflects only visible radiation
1. Diffuse Edges: Planetary nebulae typically have diffuse or fuzzy edges. This is because the expanding shell of gas and dust surrounding the central star scatters and diffuses the light emitted by the nebula. So, one correct answer is b. diffuse edges.
2. Central Star Remnant: Planetary nebulae are formed when a dying star sheds its outer layers, leaving behind a hot, dense core known as a central star remnant or white dwarf. This central star remnant emits intense ultraviolet radiation, causing the surrounding gas to glow. So, another correct answer is d. central star remnant.
The other options, a. dark area and c. spherical shape, are not specific characteristics of planetary nebulae. Dark areas typically refer to regions of space where light is blocked, while the shape of planetary nebulae can vary and may not always be spherical.