D.2 – Stellar characteristics and stellar evolution

Description

Nature of science:

Evidence: The simple light spectra of a gas on Earth can be compared to the light spectra of distant stars. This has allowed us to determine the velocity, composition and structure of stars and confirmed hypotheses about the expansion of the universe. (1.11)

Understandings:

Stellar spectra
Hertzsprung–Russell (HR) diagram
Mass–luminosity relation for main sequence stars
Cepheid variables
Stellar evolution on HR diagrams
Red giants, white dwarfs, neutron stars and black holes
Chandrasekhar and Oppenheimer–Volkoff limits

Applications and skills:

Explaining how surface temperature may be obtained from a star’s spectrum
Explaining how the chemical composition of a star may be determined from the star’s spectrum
Sketching and interpreting HR diagrams
Identifying the main regions of the HR diagram and describing the main properties of stars in these regions
Applying the mass–luminosity relation
Describing the reason for the variation of Cepheid variables
Determining distance using data on Cepheid variables
Sketching and interpreting evolutionary paths of stars on an HR diagram
Describing the evolution of stars off the main sequence
Describing the role of mass in stellar evolution

Guidance:

Regions of the HR diagram are restricted to the main sequence, white dwarfs, red giants, super giants and the instability strip (variable stars), as well as lines of constant radius
HR diagrams will be labelled with luminosity on the vertical axis and temperature on the horizontal axis
Only one specific exponent (3.5) will be used in the mass–luminosity relation
References to electron and neutron degeneracy pressures need to be made

Data booklet reference:

Theory of knowledge:

The information revealed through spectra needs a trained mind to be interpreted. What is the role of interpretation in gaining knowledge in the natural sciences? How does this differ from the role of interpretation in other areas of knowledge?

Utilization:

An understanding of how similar stars to our Sun have aged and evolved assists in our predictions of our fate on Earth

Aims:

Aim 4: analysis of star spectra provides many opportunities for evaluation and synthesis
Aim 6: software-based analysis is available for students to participate in astrophysics research

Directly related questions

20N.3.HL.TZ0.22d: Eta Aquilae A is a Cepheid variable. Explain why the brightness of Eta Aquilae A varies.
20N.3.HL.TZ0.22d: Eta Aquilae A is a Cepheid variable. Explain why the brightness of Eta Aquilae A varies.
20N.3.HL.TZ0.d: Eta Aquilae A is a Cepheid variable. Explain why the brightness of Eta Aquilae A varies.
17N.3.SL.TZ0.12d.i:
Determine the radius of Sirius B in terms of the radius of the Sun.
17N.3.SL.TZ0.12d.i:
Determine the radius of Sirius B in terms of the radius of the Sun.
17N.3.SL.TZ0.d.i:
Determine the radius of Sirius B in terms of the radius of the Sun.
17N.3.SL.TZ0.12e.i: draw the approximate positions of Sirius A, labelled A and Sirius B, labelled B.
17N.3.SL.TZ0.12e.i: draw the approximate positions of Sirius A, labelled A and Sirius B, labelled B.
17N.3.SL.TZ0.e.i: draw the approximate positions of Sirius A, labelled A and Sirius B, labelled B.
18M.3.SL.TZ2.11d.iii:
plot the position, using the letter G, of Gacrux.
18M.3.SL.TZ2.11d.iii:
plot the position, using the letter G, of Gacrux.
18M.3.SL.TZ2.d.iii:
plot the position, using the letter G, of Gacrux.
18M.3.SL.TZ2.11d.i:
draw the main sequence.
18M.3.SL.TZ2.11d.i:
draw the main sequence.
18M.3.SL.TZ2.d.i:
draw the main sequence.
18M.3.SL.TZ1.11a.i:
Suggest, using the graphs, why star X is most likely to be a main sequence star.
18M.3.SL.TZ1.11a.i:
Suggest, using the graphs, why star X is most likely to be a main sequence star.
18M.3.SL.TZ1.a.i:
Suggest, using the graphs, why star X is most likely to be a main sequence star.
18M.3.SL.TZ1.11b.i:
Write down the luminosity of star X (L_X) in terms of the luminosity of the Sun (L_s).
18M.3.SL.TZ1.11b.i:
Write down the luminosity of star X (L_X) in terms of the luminosity of the Sun (L_s).
18M.3.SL.TZ1.b.i:
Write down the luminosity of star X (L_X) in terms of the luminosity of the Sun (L_s).
18M.3.SL.TZ1.11c:
Star X is likely to evolve into a stable white dwarf star.

Outline why the radius of a white dwarf star reaches a stable value.
18M.3.SL.TZ1.11c:
Star X is likely to evolve into a stable white dwarf star.

Outline why the radius of a white dwarf star reaches a stable value.
18M.3.SL.TZ1.c:
Star X is likely to evolve into a stable white dwarf star.

Outline why the radius of a white dwarf star reaches a stable value.
18N.3.SL.TZ0.12d: Describe the stages in the evolution of Epsilon Indi from the point when it leaves the main...
18N.3.SL.TZ0.12d: Describe the stages in the evolution of Epsilon Indi from the point when it leaves the main...
18N.3.SL.TZ0.d: Describe the stages in the evolution of Epsilon Indi from the point when it leaves the main...
18N.3.SL.TZ0.12b:
Epsilon Indi is a main sequence star. Show that the mass of Epsilon Indi is 0.64 ${M_ \odot }$ .
18N.3.SL.TZ0.12b:
Epsilon Indi is a main sequence star. Show that the mass of Epsilon Indi is 0.64 ${M_ \odot }$ .
18N.3.SL.TZ0.b:
Epsilon Indi is a main sequence star. Show that the mass of Epsilon Indi is 0.64 ${M_ \odot }$ .
18N.3.SL.TZ0.12a.ii: Using the axis, draw the variation with wavelength of the intensity of the radiation emitted by...
18N.3.SL.TZ0.12a.ii: Using the axis, draw the variation with wavelength of the intensity of the radiation emitted by...
18N.3.SL.TZ0.a.ii: Using the axis, draw the variation with wavelength of the intensity of the radiation emitted by...
18N.3.HL.TZ0.18a.i:
Determine the peak wavelength of the radiation emitted by Epsilon Indi.
18N.3.HL.TZ0.18a.i:
Determine the peak wavelength of the radiation emitted by Epsilon Indi.
18N.3.HL.TZ0.a.i:
Determine the peak wavelength of the radiation emitted by Epsilon Indi.
18N.3.SL.TZ0.12c: Describe how the chemical composition of a star may be determined.
18N.3.SL.TZ0.12c: Describe how the chemical composition of a star may be determined.
18N.3.SL.TZ0.c: Describe how the chemical composition of a star may be determined.
18N.3.HL.TZ0.18b:
Epsilon Indi is a main sequence star. Show that the mass of Epsilon Indi is 0.64 ${M_ \odot }$ .
18N.3.HL.TZ0.18b:
Epsilon Indi is a main sequence star. Show that the mass of Epsilon Indi is 0.64 ${M_ \odot }$ .
18N.3.HL.TZ0.b:
Epsilon Indi is a main sequence star. Show that the mass of Epsilon Indi is 0.64 ${M_ \odot }$ .
18N.3.HL.TZ0.18a.ii: Using the axis, draw the variation with wavelength of the intensity of the radiation emitted by...
18N.3.HL.TZ0.18a.ii: Using the axis, draw the variation with wavelength of the intensity of the radiation emitted by...
18N.3.HL.TZ0.a.ii: Using the axis, draw the variation with wavelength of the intensity of the radiation emitted by...
18N.3.HL.TZ0.18d: Describe the stages in the evolution of Epsilon Indi from the point when it leaves the main...
18N.3.HL.TZ0.18d: Describe the stages in the evolution of Epsilon Indi from the point when it leaves the main...
18N.3.HL.TZ0.d: Describe the stages in the evolution of Epsilon Indi from the point when it leaves the main...
19M.3.SL.TZ2.13aii: Explain how Cepheid variables are used to determine distances.
19M.3.SL.TZ2.13aii: Explain how Cepheid variables are used to determine distances.
19M.3.SL.TZ2.aii: Explain how Cepheid variables are used to determine distances.
19M.3.SL.TZ2.15a: Identify, on the HR diagram, the position of the Sun. Label the position S.
19M.3.SL.TZ2.15a: Identify, on the HR diagram, the position of the Sun. Label the position S.
19M.3.SL.TZ2.a: Identify, on the HR diagram, the position of the Sun. Label the position S.
19M.3.SL.TZ2.15b: Suggest the conditions that will cause the Sun to become a red giant.
19M.3.SL.TZ2.15b: Suggest the conditions that will cause the Sun to become a red giant.
19M.3.SL.TZ2.b: Suggest the conditions that will cause the Sun to become a red giant.
19M.3.SL.TZ2.13bii:
Calculate the peak surface temperature of δ-Cephei.
19M.3.SL.TZ2.13bii:
Calculate the peak surface temperature of δ-Cephei.
19M.3.SL.TZ2.bii:
Calculate the peak surface temperature of δ-Cephei.
19M.3.SL.TZ2.15c:
Outline why the Sun will maintain a constant radius after it becomes a white dwarf.
19M.3.SL.TZ2.15c:
Outline why the Sun will maintain a constant radius after it becomes a white dwarf.
19M.3.SL.TZ2.c:
Outline why the Sun will maintain a constant radius after it becomes a white dwarf.
19N.3.SL.TZ0.10c(iii):
Calculate the ratio $\frac{mass of Eta Cassiopeiae A}{mass of the Sun}$ .
19N.3.SL.TZ0.10c(iii):
Calculate the ratio $\frac{mass of Eta Cassiopeiae A}{mass of the Sun}$ .
19N.3.SL.TZ0.c(iii):
Calculate the ratio $\frac{mass of Eta Cassiopeiae A}{mass of the Sun}$ .
19N.3.SL.TZ0.10c(i): On the HR diagram, draw the present position of Eta Cassiopeiae A.
19N.3.SL.TZ0.10c(i): On the HR diagram, draw the present position of Eta Cassiopeiae A.
19N.3.SL.TZ0.c(i): On the HR diagram, draw the present position of Eta Cassiopeiae A.
19N.3.SL.TZ0.10c(iv):
Deduce the final evolutionary state of Eta Cassiopeiae A.
19N.3.SL.TZ0.10c(iv):
Deduce the final evolutionary state of Eta Cassiopeiae A.
19N.3.SL.TZ0.c(iv):
Deduce the final evolutionary state of Eta Cassiopeiae A.
17N.3.SL.TZ0.12a: State what is meant by a binary star.
17N.3.SL.TZ0.12a: State what is meant by a binary star.
17N.3.SL.TZ0.a: State what is meant by a binary star.
17N.3.SL.TZ0.12b:
The peak spectral line of Sirius B has a measured wavelength of 115 nm. Show that the surface temperature of Sirius B is about 25 000 K.
17N.3.SL.TZ0.12b:
The peak spectral line of Sirius B has a measured wavelength of 115 nm. Show that the surface temperature of Sirius B is about 25 000 K.
17N.3.SL.TZ0.b:
The peak spectral line of Sirius B has a measured wavelength of 115 nm. Show that the surface temperature of Sirius B is about 25 000 K.
17N.3.SL.TZ0.12c:
The mass of Sirius B is about the same mass as the Sun. The luminosity of Sirius B is 2.5 % of the luminosity of the Sun. Show, with a calculation, that Sirius B is not a main sequence star.
17N.3.SL.TZ0.12c:
The mass of Sirius B is about the same mass as the Sun. The luminosity of Sirius B is 2.5 % of the luminosity of the Sun. Show, with a calculation, that Sirius B is not a main sequence star.
17N.3.SL.TZ0.c:
The mass of Sirius B is about the same mass as the Sun. The luminosity of Sirius B is 2.5 % of the luminosity of the Sun. Show, with a calculation, that Sirius B is not a main sequence star.
17N.3.SL.TZ0.12d.ii: Identify the star type of Sirius B.
17N.3.SL.TZ0.12d.ii: Identify the star type of Sirius B.
17N.3.SL.TZ0.d.ii: Identify the star type of Sirius B.
17N.3.SL.TZ0.12e.ii: sketch the expected evolutionary path for Sirius A.
17N.3.SL.TZ0.12e.ii: sketch the expected evolutionary path for Sirius A.
17N.3.SL.TZ0.e.ii: sketch the expected evolutionary path for Sirius A.
18M.3.SL.TZ1.11a.ii:
Show that the temperature of star X is approximately 10 000 K.
18M.3.SL.TZ1.11a.ii:
Show that the temperature of star X is approximately 10 000 K.
18M.3.SL.TZ1.a.ii:
Show that the temperature of star X is approximately 10 000 K.
18M.3.SL.TZ1.11b.ii:
Determine the radius of star X (R_X) in terms of the radius of the Sun (R_s).
18M.3.SL.TZ1.11b.ii:
Determine the radius of star X (R_X) in terms of the radius of the Sun (R_s).
18M.3.SL.TZ1.b.ii:
Determine the radius of star X (R_X) in terms of the radius of the Sun (R_s).
18M.3.SL.TZ1.11b.iii:
Estimate the mass of star X (M_X) in terms of the mass of the Sun (M_s).
18M.3.SL.TZ1.11b.iii:
Estimate the mass of star X (M_X) in terms of the mass of the Sun (M_s).
18M.3.SL.TZ1.b.iii:
Estimate the mass of star X (M_X) in terms of the mass of the Sun (M_s).
18M.3.SL.TZ2.11d.ii:
plot the position, using the letter P, of the main sequence star P you calculated in (b).
18M.3.SL.TZ2.11d.ii:
plot the position, using the letter P, of the main sequence star P you calculated in (b).
18M.3.SL.TZ2.d.ii:
plot the position, using the letter P, of the main sequence star P you calculated in (b).
18M.3.SL.TZ2.11e:
Discuss, with reference to its change in mass, the evolution of star P from the main sequence until its final stable phase.
18M.3.SL.TZ2.11e:
Discuss, with reference to its change in mass, the evolution of star P from the main sequence until its final stable phase.
18M.3.SL.TZ2.e:
Discuss, with reference to its change in mass, the evolution of star P from the main sequence until its final stable phase.
18N.3.SL.TZ0.12a.i:
Determine the peak wavelength of the radiation emitted by Epsilon Indi.
18N.3.SL.TZ0.12a.i:
Determine the peak wavelength of the radiation emitted by Epsilon Indi.
18N.3.SL.TZ0.a.i:
Determine the peak wavelength of the radiation emitted by Epsilon Indi.
18N.3.HL.TZ0.18c:
The Sun will spend about nine billion years on the main sequence. Calculate how long Epsilon Indi will spend on the main sequence.
18N.3.HL.TZ0.18c:
The Sun will spend about nine billion years on the main sequence. Calculate how long Epsilon Indi will spend on the main sequence.
18N.3.HL.TZ0.c:
The Sun will spend about nine billion years on the main sequence. Calculate how long Epsilon Indi will spend on the main sequence.
19M.3.SL.TZ2.13ai: Outline the processes that produce the change of luminosity with time of Cepheid variables.
19M.3.SL.TZ2.13ai: Outline the processes that produce the change of luminosity with time of Cepheid variables.
19M.3.SL.TZ2.ai: Outline the processes that produce the change of luminosity with time of Cepheid variables.
19N.3.SL.TZ0.10b(i):
The peak wavelength of radiation from Eta Cassiopeiae A is 490 nm. Show that the surface temperature of Eta Cassiopeiae A is about 6000 K.
19N.3.SL.TZ0.10b(i):
The peak wavelength of radiation from Eta Cassiopeiae A is 490 nm. Show that the surface temperature of Eta Cassiopeiae A is about 6000 K.
19N.3.SL.TZ0.b(i):
The peak wavelength of radiation from Eta Cassiopeiae A is 490 nm. Show that the surface temperature of Eta Cassiopeiae A is about 6000 K.
19N.3.SL.TZ0.10c(ii): State the star type of Eta Cassiopeiae A.
19N.3.SL.TZ0.10c(ii): State the star type of Eta Cassiopeiae A.
19N.3.SL.TZ0.c(ii): State the star type of Eta Cassiopeiae A.
20N.3.SL.TZ0.17a:
Show by calculation that Eta Aquilae A is not on the main sequence.
20N.3.SL.TZ0.17a:
Show by calculation that Eta Aquilae A is not on the main sequence.
20N.3.SL.TZ0.a:
Show by calculation that Eta Aquilae A is not on the main sequence.
20N.3.SL.TZ0.17d: Eta Aquilae A is a Cepheid variable. Explain why the brightness of Eta Aquilae A varies.
20N.3.SL.TZ0.17d: Eta Aquilae A is a Cepheid variable. Explain why the brightness of Eta Aquilae A varies.
20N.3.SL.TZ0.d: Eta Aquilae A is a Cepheid variable. Explain why the brightness of Eta Aquilae A varies.
20N.3.HL.TZ0.22a:
Show by calculation that Eta Aquilae A is not on the main sequence.
20N.3.HL.TZ0.22a:
Show by calculation that Eta Aquilae A is not on the main sequence.
20N.3.HL.TZ0.a:
Show by calculation that Eta Aquilae A is not on the main sequence.
21N.1.SL.TZ0.30: Which is correct for a black-body radiator? A. The power it emits from a unit surface area...
21N.1.SL.TZ0.30: Which is correct for a black-body radiator? A. The power it emits from a unit surface area...

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D.2 – Stellar characteristics and stellar evolution

Description

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