Question 1

Observing star clusters will give astronomers needed data for stellar evolution because all the stars in the cluster have the same ____.
A) masses
B) temperatures
C) ages
D) luminosities
E) apparent magnitudes

Accepted Answer

All stars in a cluster formed around the same time, so they have the same age. This makes it an excellent place for astronomers to study the stages of stellar evolution, as they can compare stars of the same age and track their progression through different stages of their lives.

Question 2

Giant and supergiant stars are rare because they do not form as often as main sequence stars.

Accepted Answer

Giant and supergiant stars are stages in the evolution of stars, not initial formation states. All stars begin their lives as main sequence stars and may become giants or supergiants as they age and their internal processes change.

Question 3

As a star like the Sun exhausts hydrogen in its core, the outer layers of the star become hotter and more luminous.

Accepted Answer

As a star like the Sun exhausts hydrogen in its core, it expands and cools on the surface, becoming a red giant, although the core itself becomes hotter, leading to the outer layers becoming more luminous due to the increased size, not because they are hotter.

Question 4

All the elements heavier than helium on the periodic table, including the ones in your body, were created in the cores of massive stars.

Accepted Answer

This is known as stellar nucleosynthesis and scientific research supports this theory.

Question 5

The energy emitted from the surface of a main sequence star is less than the energy generated in the core.

Accepted Answer

The energy emitted from the surface of a main sequence star is essentially equal to the energy generated in its core, as energy produced in the core is transported to the surface and radiated into space, maintaining an energy balance.

Question 6

Observing star clusters will give astronomers needed data for stellar evolution because all the stars are the same age.

Accepted Answer

Star clusters are formed from the same cloud of gas and dust, so all the stars within a cluster have the same age. This makes them useful for studying stellar evolution because differences in brightness, temperature, and other properties can be attributed to variations in mass, composition, and stage of evolution.

Question 7

Astronomers can determine the interiors of main sequence stars by _____.
A) studying their atmospheres
B) creating stellar models
C) detailed observations of the Sun
D) using the Hertzsprung-Russell Stellar Model (HRSM)
E) satellite observations of the closest stars

Accepted Answer

Astronomers can determine the interiors of main sequence stars by creating stellar models, which use stellar properties like mass, radius, and composition to simulate the conditions and behavior inside the star. This allows astronomers to study things like the temperature, density, and energy production in the star's core, which can provide insight into its evolution and overall properties.

Question 8

As a one-solar-mass star evolves off the main sequence, it will probably undergo a _____.
A) nova burnout
B) helium flash
C) hydrogen flash
D) helium bang
E) carbon flash

Accepted Answer

As a one-solar-mass star evolves off the main sequence, it will eventually exhaust the hydrogen in its core and start fusing helium. This process will result in a helium flash, where the core ignites in a burst of energy due to the sudden release of fusion energy.

Question 9

When the Sun moves off the main sequence, it will initially become a red supergiant.

Accepted Answer

This is a correct statement. As the Sun's core runs out of hydrogen fuel, it will begin to fuse helium in its core and expand into a red supergiant.

Question 10

There is a mass-luminosity relationship because stars support their weight by generating energy, and more massive stars have more weight to support.

Accepted Answer

The mass-luminosity relationship is a well-established principle in astronomy, which states that more massive stars have higher luminosities (i.e., they are more luminous) than less massive stars of the same age and composition. This is because stars generate energy through nuclear fusion, which is the process by which light elements are fused together to form heavier elements, such as hydrogen being fused into helium. More massive stars have more fuel to burn, which generates more energy and heat, making them brighter and more luminous. This is why the most massive stars, such as blue supergiants, can be millions of times more luminous than the Sun.

Question 11

The age of a star cluster can be approximated by finding its turnoff point in the distribution of data points that represent stars on the H-R Diagram.

Accepted Answer

The turnoff point in the H-R Diagram corresponds to the age of the star cluster, as it represents the moment when the most massive stars have exhausted their fuel and left the main sequence. Therefore, the age of a star cluster can be estimated by finding its turnoff point.

Question 12

Stellar models can easily be accomplished by using a simple hand calculator.

Accepted Answer

Stellar models involve complex calculations and require advanced software and supercomputers to be accurately done. Hand calculators are insufficient for this task.

Question 13

Degenerate matter has two peculiar properties that can affect a star.  One is that the degenerate gas resists compression, and the other is that the degenerate gas ____.
A) is not density dependent
B) does depend on temperature
C) does not depend on temperature
D) is not pressure dependent.
E) does depend on the type of nuclei present

Accepted Answer

Degenerate gas does not depend on temperature, only on density. This is because the electrons in the gas are already in the lowest available energy states and cannot be compressed any further. Therefore, increasing the temperature will not affect the pressure of the gas.

Question 14

What is the upper limit of a brown dwarf's size?
A) no upper limit
B) 0.50 solar masses
C) 0.10 solar masses
D) 0.08 solar masses
E) less than 0.08 solar masses

Accepted Answer

The answer of What is the upper limit of a...

Question 15

Globular clusters have approximately how many stars?
A) 100,000 - 1,000,000
B) 10,000 - 90,000
C) 5,000 - 10,000
D) 1000 - 5000
E) less than 1000

Accepted Answer

Globular clusters are large collections of stars, typically containing 100,000 to 1,000,000 stars. These dense clusters are among the oldest objects in the universe and are found in the halos of galaxies, including the Milky Way.

Question 16

To determine the structure of the interior of a star, astronomers must balance density, luminosity, and ____.
A) mass
B) temperature
C) mass and temperature
D) mass and opacity
E) temperature and opacity

Accepted Answer

In order to determine the structure of the interior of a star, astronomers must take into account its density, luminosity, and mass and temperature. The mass and temperature of a star are crucial factors in understanding its structure and the way it generates energy. Density and luminosity alone do not provide enough information to determine the interior structure of a star. Opacity is also a factor, but it is related to temperature and therefore falls under the category of mass and temperature. Therefore, the best choice is C, mass and temperature.

Question 17

Astronomers determine the internal structure of a star by using stellar models, since they cannot "see" into the interior of a star.

Accepted Answer

Astronomers can only observe the outer layers of a star, and therefore must use models to understand the internal structure.

Question 18

The helium flash stage will always completely destroy a star and any planets nearby it

Accepted Answer

The helium flash stage occurs in low- to medium-mass stars during the red giant phase, and while it is a violent event, it does not completely destroy the star or any planets nearby it. After the helium flash, the star will eventually stabilize and become a stable helium-burning star known as a "horizontal branch star".

Question 19

Brown dwarfs are ____.
A) stars with a very thick dust sphere around them, so they appear "brown"
B) low mass M type stars with hundreds of planets
C) an anomaly because they are extremely small but have relatively high temperature
D) protostars that could not ignite the fusion of hydrogen at their core
E) has a surface temperature of 2500 K by fusing hydrogen

Accepted Answer

Brown dwarfs are objects that have a mass less than that of a star, but more than that of a planet. They form like stars, but their cores are not massive enough to start nuclear fusion of hydrogen into helium. Thus, they are sometimes called "failed stars." They emit heat and light from their surface, but not from fusion like stars.

Question 20

The fusion of helium into carbon will take a temperature of at least
A) 5 million degrees Kelvin
B) 10 million degrees Kelvin
C) 50 million degrees Kelvin
D) 100 million degrees Kelvin
E) 600 million degrees Kelvin

Accepted Answer

The answer of The fusion of helium into carbon will...

Quiz 12: Stellar Evolution

Observing star clusters will give astronomers needed data for stellar evolution because all the stars in the cluster have the same ____.

Giant and supergiant stars are rare because they do not form as often as main sequence stars.

As a star like the Sun exhausts hydrogen in its core, the outer layers of the star become hotter and more luminous.

All the elements heavier than helium on the periodic table, including the ones in your body, were created in the cores of massive stars.

The energy emitted from the surface of a main sequence star is less than the energy generated in the core.

Observing star clusters will give astronomers needed data for stellar evolution because all the stars are the same age.

Astronomers can determine the interiors of main sequence stars by _____.

As a one-solar-mass star evolves off the main sequence, it will probably undergo a _____.

When the Sun moves off the main sequence, it will initially become a red supergiant.

There is a mass-luminosity relationship because stars support their weight by generating energy, and more massive stars have more weight to support.

The age of a star cluster can be approximated by finding its turnoff point in the distribution of data points that represent stars on the H-R Diagram.

Stellar models can easily be accomplished by using a simple hand calculator.

Degenerate matter has two peculiar properties that can affect a star. One is that the degenerate gas resists compression, and the other is that the degenerate gas ____.

What is the upper limit of a brown dwarf's size?

Globular clusters have approximately how many stars?

To determine the structure of the interior of a star, astronomers must balance density, luminosity, and ____.

Astronomers determine the internal structure of a star by using stellar models, since they cannot "see" into the interior of a star.

The helium flash stage will always completely destroy a star and any planets nearby it

Brown dwarfs are ____.

The fusion of helium into carbon will take a temperature of at least