Astronomy Unit 7

Ranking Task: Exploring the Different Stages of Star Birth Part A: The following figures show four stages that occur during the formation of a one-solar-mass star. Rank these stages based on the order in which they occur, from first to last.

Ranking Task: Exploring the Different Stages of Star Birth Part B: The following figures show four stages that occur during the formation of a one-solar-mass star. Rank these stages based on the central temperature, from highest to lowest.

Ranking Task: Exploring the Different Stages of Star Birth Part C: The following figures show four stages that occur during the formation of a one-solar-mass star. Rank these stages based on their rotation rate, from fastest to slowest. (Assume that the angular momentum of the forming star is conserved throughout the formation process, though in fact it may shed some angular momentum by ejecting material into interstellar space.)

Sorting Task: Protostar or Main-Sequence Star Each item following is a characteristic of a one-solar-mass star either during its protostar phase or during its main-sequence phase. Match the items to the appropriate phase.

Ranking Task: How Star Properties Affect Star Formation Part A: The following figures show the spectral types of four main-sequence stars. Rank them based on the time each takes, from longest to shortest, to go from a protostar to a main-sequence star during the formation process.

Ranking Task: How Star Properties Affect Star Formation Part B: Provided following are the spectral types of four different main-sequence stars. Rank the stars based on the strength of the radiation pressure that pushes outward as they are forming, from highest pressure to lowest pressure.

Ranking Task: How Star Properties Affect Star Formation Part C: Provided following are four different ranges of stellar masses. Rank the stellar mass ranges based on how many stars in each range you would expect to be born in a star cluster, from highest number to lowest number.

Ranking Task: Properties of Stars in the Milky Way Galaxy Part A: The following figures show several stars found in the disk and halo of the Milky Way Galaxy. Rank the stars based on their current age, from oldest to youngest. If two (or more) stars have approximately the same age (that is, ages within a few million years), rank them as equal by dragging one on top of the other(s).

Ranking Task: Properties of Stars in the Milky Way Galaxy Part B: Listed following are several stars found in the disk and halo of the Milky Way Galaxy. Assume that both the blue and yellow disk stars are members of the same open cluster. Rank the stars based on the abundance of elements heavier than carbon that you would expect to find in each of the stars, from highest to lowest. If you expect two (or more) stars to have approximately the same abundance, rank them as equal by dragging one on top of the other(s).

Ranking Task: The Life of a High-Mass Main Sequence Star Part A: Provided following are various stages during the life of a high-mass star. Rank the stages based on when they occur, from first to last.

Ranking Task: The Life of a High-Mass Main Sequence Star Part B: Provided following are various elements that can be produced during fusion in the core of a high mass main sequence star. Rank these elements based on when they are produced, from first to last.

Ranking Task: The Life of a Low-Mass Main-Sequence Star Part A: The following figures show various stages during the life of a star with the same mass as the Sun. Rank the stages based on when they occur, from first to last.

Ranking Task: The Life of a Low-Mass Main-Sequence Star Part B: Assume that all four H-R diagrams below represent a star in different stages of its life, after it starts to fuse hydrogen in its core. Rank the HR diagrams based on when each stage occurs, from first to last.

Sorting Task: High- and Low-Mass Stars Listed following are characteristics that describe either high-mass or low-mass stars. Match these characteristics to the appropriate category.

Process of Science: Stars Leaving the Main Sequence Part A: A star is in hydrostatic equilibrium when the outward push of pressure due to core burning is exactly in balance with the inward pull of gravity. When the hydrogen in a star's core has been used up, burning ceases, and gravity and pressure are no longer in balance. This causes the star to undergo significant changes. Which of the following evolutionary changes would bring a star back into hydrostatic equilibrium?

Process of Science: Stars Leaving the Main Sequence Part B: When a star's core hydrogen has been fully depleted via hydrogen burning, the star becomes unstable. The internal structure of the star changes as a result of the new instabilities within its interior. Which of the diagrams below shows the internal structure of a star immediately after running out of its core hydrogen?

Process of Science: Stars Leaving the Main Sequence Part C: As you learned in Part B, a nonburning helium core surrounded by a shell of hydrogen-burning gas characterizes the subgiant stage of stellar evolution. As time goes on, the star continues to evolve, and eventually, it becomes a red giant. Rank the stages a star goes through as it evolves from a subgiant into a red giant, from latest to earliest.

Process of Science: Stars Leaving the Main Sequence Part D: Depending on its mass, it can take millions to trillions of years for a star to evolve from a main-sequence star to a red giant. Despite this astronomical length of time, astronomers are confident in their models of stellar evolution. Which of the following statements best describe why astronomers firmly believe that their models of stellar evolution are correct?

How White Dwarfs Can Produce Novae Part A: No nuclear reactions occur in the interior of a white dwarf. Its brilliance comes from stored heat. Therefore, the fate of an isolated white dwarf is to slowly lose its stored energy and dim over a long period of time. However, if a white dwarf is a member of a binary-star system with specific properties, the white dwarf can become explosively active. Label the components of such a binary-star system capable of producing a nova event.

How White Dwarfs Can Produce Novae Part B: In a binary-star system that produces a nova, the white dwarf pulls matter from the companion star. The matter forms an accretion disk that orbits the white dwarf. Then a specific sequence of events must take place for a nova event to occur.

How White Dwarfs Can Produce Novae Part C: A nova produces a characteristic light curve, which provides astronomers with details about the nova event. Select the appropriate light curve that shows how a nova's brightness changes over time.

Accretion

White dwarf

Chandrasekhar limit

Characteristics and Mechanisms of the Supernovae Types Part A: Rank the following steps that lead to a Type I supernova event in order of when they occur from first to last.

Characteristics and Mechanisms of the Supernovae Types Part B: Rank the following steps that lead to a Type II supernova event in order of when they occur from first to last.

Characteristics and Mechanisms of the Supernovae Types Part C: Each supernova type is distinct in initial components, process, and observational properties. Sort the following characteristics as to whether they describe a Type I or Type II supernova.