Crash Course Astronomy: White Dwarfs and Planetary Nebulae

The video explores the fate of low mass stars, focusing on the formation of white dwarfs and planetary nebulae. White dwarfs are dense, hot remnants of stars, while planetary nebulae are glowing shells of gas expelled by dying stars. The video discusses the unique characteristics of white dwarfs, the formation and diverse shapes of planetary nebulae, and the role of binary stars and planets in shaping these nebulae. It concludes with a look at the brief lifespan of planetary nebulae and a preview of future topics on more massive stars.

What happens to the Sun when it runs out of helium to fuse?

• It continues to fuse carbon.

• It forms a white dwarf.

• It explodes as a supernova.

• It becomes a black hole.

What is the primary force that supports a white dwarf against gravity?

• Nuclear fusion pressure

• Electron degeneracy pressure

• Magnetic pressure

• Thermal pressure

Why are white dwarfs difficult to observe despite their high temperatures?

• They are hidden by gas clouds.

• They emit only infrared light.

• They are too far away.

• They are very small and faint.

What is a planetary nebula?

• A type of planet

• A black hole surrounded by gas

• A region of star formation

• A glowing shell of gas around a white dwarf

What can cause the diverse shapes of planetary nebulae?

• The presence of dark matter

• The star's initial mass

• The star's magnetic field

• The presence of binary stars or planets

What element is primarily responsible for the green glow in planetary nebulae?

• Oxygen

• Hydrogen

• Helium

• Nitrogen

Why do planetary nebulae have a short lifespan?

• They are consumed by nearby stars.

• They are quickly absorbed by black holes.

• They are destroyed by supernova explosions.

• The gas expands and thins out, stopping the glow.

What is the likely fate of the Sun in terms of forming a planetary nebula?

• It will explode as a supernova.

• It will not form a visible planetary nebula.

• It will form a bright planetary nebula.

• It will become a neutron star.

What happens to stars more massive than the Sun when they die?

• They explode as supernovae.

• They turn into red giants.

• They form white dwarfs.

• They become black holes.

What is the main reason the Sun will not form a planetary nebula?

• It will become a black hole instead.

• It is not massive enough.

• It will explode as a supernova.

• It will be consumed by a nearby star.