Stellar Evolution

Multiple Choice

Which of the following characteristics determines the life cycle of a star?

• Luminosity

• Temperature

• Color

• Mass

Multiple Choice

What is the source of energy for the Sun?

• nuclear fusion

• burning coal

• burning of solar gases

• splitting of atoms

Multiple Choice

Our Sun, along with most of the stars in our neighborhood, probably formed …

• … about 10 million years ago.

• … a few million years ago.

• … hundreds of millions of years ago.

• … billions of years ago.

• … at the beginning of the universe.

Multiple Choice

What is the most common type of star?

• Supergiant

• Main Sequence

• Red Giant

• White Dwarf

Multiple Choice

What type of star is the Sun?

• Supergiant

• Red Giant

• Main Sequence

• White Dwarf

Multiple Choice

What do astronomers mean when they talk about stars "burning"

• "Burning" refers to the ignition of hydrogen gas

• Newly formed stars burn off excess gas around them

• Hot stars burn up the surfaces of planets that are too close

• "Burning" is the term for fusion

Multiple Choice

What is the main difference between white and red dwarfs

• White dwarfs are larger than red dwarfs

• White dwarfs are cooler than red dwarfs

• White dwarfs don't have active fusion while red dwarfs do

• White dwarfs always form in pairs while red dwarfs always form alone

Multiple Choice

What is the name of the cloud that a star is formed in?

• Nebula / Stellar Nursery

• Supernova

• Main Sequence

• Dwarf

Reorder

A protostar is formed in a nebula,
after large collections of gas and dust are drawn together by gravity.
Put the steps of creating a protostar in order.

• condense

• heat up

• begins to spin (rotate on its axis)

• becomes spherical

1

2

3

4

• 1
• 2
• 3
• 4

Multiple Choice

Proto-stars collapse to form stars. What stops them from collapsing?

• Their inward force of gravity decreases and becomes zero

• They generate enough frictional heat to balance gravity

• They spin fast enough to balance gravity

• Fusion starts to balance gravity

Multiple Choice

Which event marks the birth of a star?

• collapse of an interstellar cloud

• formation of the planetary nebula

• fusion of hydrogen atoms into helium atoms

• formation of a photosphere

• instability in an interstellar cloud

Multiple Choice

What is a brown dwarf?

• A "failed" star too small for sustained fusion

• A star with large amounts of carbon and silicon

• The dead cores of stars

• Stars shrouded in opaque dust and gas

Multiple Choice

What causes stars to exit the main sequence?

• They use up all of their hydrogen

• They run out of hydrogen in their core

• Too much of their mass gets used up through fusion

• They cool off too much for fusion to work propperly

Multiple Choice

After the main sequence, a low/Intermediate mass star becomes a

• black dwarf
• protostar
• red giant
• supergiant

Multiple Choice

In the red giant phase, the star begins fusing __________.

• Silicon and Oxygen only

• Elements with higher mass than Iron

• Elements between Helium and Iron

• Helium and a little bit of Carbon and Oxygen

Multiple Choice

What is a planetary nebula?

• A nebula that creates protostars.

• A nebula that forms after a red giant blows off its outer layers.

• The end stage of a massive star.

• A failed star that isn't big enough to have fusion

Multiple Choice

The core of a red giant collapses to form a _________.

• Supernova

• Nebula

• White Dwarf

• Main Sequence Star

Multiple Choice

A small White Dwarf has a diameter similar to:

• The Sun

• The Earth

• The Moon

• A basketball

Reorder

Put the steps in the life cycle of a low/intermediate mass star in order.

• gas and dust condense to form a protostar

• fusion of H begins and the star enters the main sequence

• fusion of H stops and the star expands into a red giant fusing He

• all fusion stops and the outer layers expand in a planetary nebula

• the core collapses into a white dwarf

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

Multiple Choice

What feature/quality do proto-stars lack that keeps them from being true stars?

• They don't have fusion

• They're too small

• They aren't hot enough

• They're rotating too fast

Multiple Choice

Compared to lower mass protostars, higher mass protostars enter the main sequence…

• …faster and at a higher luminosity and temperature.

• …faster and at a lower luminosity and temperature.

• …slower and at a higher luminosity and temperature.

• …slower and at a lower luminosity and temperature.

• …at the same rate, but at a higher luminosity and temperature.

Multiple Choice

After the main sequence, a high /very high mass star becomes a

• black dwarf

• protostar

• red giant

• supergiant

Multiple Choice

High mass stars produce onion-like layers. What are these layers made of?

• Regions of hotter and colder material

• Alternating regions of radiation and convection zones

• Shells of other elements fusing

• Layers of different degenerate matter

Multiple Choice

In a supergiant, when an iron core is reached, a high / very high mass star collapses before exploding in a _________.

• black hole

• neutron star

• explosion

• supernova

Multiple Choice

A neutron star is

• The end phase of a high mass star.

• A star made up of only protons.

• The type of star you have before it turns into a black hole.

Multiple Choice

After very high mass stars supernova, their cores collapse to form this celestial object that is so strong that not even light can escape

• Supernova

• White dwarf

• Nebula

• Black hole

Reorder

Put the steps in the life cycle of a high / very high mass star in order.

• gas and dust condense to form a protostar

• fusion of H begins and the star enters the main sequence

• fusion of H stops and the star expands into a supergiant fusing elements up to iron

• all fusion stops, and triggers a supernova

• the core collapses into a neutron star or black hole

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

Labelling

Label the stellar evolution diagram with the processes that is happening inside the core of the star.

Drag labels to their correct position on the image

fusion stops

fusion of He

fusion of H

core collapses

Multiple Select

Which of the options below are possible after any star "dies" (choose all that apply)

• supernova remnant

• planetary nebula

• white dwarf

• neutron star

• black hole