Unit 3 Activity: The Universe Stellar Evolution

Do all protostars become stars? Why or why not?

• Yes, all protostars eventually become stars.

• No, some protostars do not have enough mass to initiate nuclear fusion.

• Yes, but only if they are in a binary system.

• No, because they all become black holes instead.

Which type of star is the brightest?

• Red dwarf

• White dwarf

• Blue supergiant

• Yellow giant

How is a massive star’s stage 4 different than an average star’s stage 4?

• Massive stars expand into red giants, while average stars become white dwarfs.

• Massive stars undergo supernova explosions, while average stars do not.

• Massive stars form neutron stars or black holes, while average stars form planetary nebulae.

• Massive stars become blue giants, while average stars become red giants.

Why do some massive stars become neutron stars and others black holes?

• It depends on the star's initial mass.

• It depends on the star's chemical composition.

• It depends on the star's distance from Earth.

• It depends on the star's rotational speed.

What is the primary factor that determines whether a protostar will become a main-sequence star?

• Its temperature

• Its mass

• Its luminosity

• Its distance from the galactic center

Which of the following stages is common to both massive stars and average stars?

• Red giant

• White dwarf

• Supernova

• Black hole

What process marks the transition of a protostar into a main-sequence star?

• Gravitational collapse

• Nuclear fusion of hydrogen into helium

• Formation of a planetary nebula

• Accretion of interstellar material

Which of the following is a characteristic of a neutron star?

• It is composed mostly of iron.

• It has a very strong magnetic field.

• It is larger than a red giant.

• It is cooler than a white dwarf.

What happens to the core of a massive star after a supernova explosion?

• It becomes a white dwarf.

• It becomes a neutron star or black hole.

• It disperses into space.

• It forms a new protostar.

Which factor is most critical in determining the end state of a star?

• The star's age

• The star's mass

• The star's temperature

• The star's luminosity