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Astronomy 12
The Birth & Death of Stars
Levelled Curriculum Project
Due Date:
Learning Outcomes (Students will…):
 describe the life cycles of stars
 compare the compositions of stars at different stages of their life cycles
 describe and apply classification systems and nomenclature used in the classification of stars
Instructions:
 Cite references for any sources used in an activity (especially essays). Use any format (MLA, APA, ApJ).
 Students who have difficulty acquiring information sources should seek assistance from Mr. Jennings
Grading Structure:
 Up to a grade of 75% for the satisfactory completion of one Level 1 activity and one Level 2 activity.
 Up to a grade of 80% for the satisfactory completion of two Level 1 activities and one Level 2 activity.
 Up to a grade of 85% for the satisfactory completion of one Level 1 activity and two Level 2 activities.
 Up to a grade of 90% for the satisfactory completion of one Level 3 activity.
 Up to a grade of 95% for the satisfactory completion of one Level 3 activity and one Level 2 activity.
 Up to a grade of 100% for the satisfactory completion of one Level 3 activity and two Level 2 activities OR two
Level 3 activities.
N.B.: Students must submit the Hertzsprung-Russell Diagram activity and Stellar Evolution
Worksheet to receive a grade for this project.
Level 1
Level 2
Activity Description
A. Submit a completed set of Cornell class notes.
B. Create a pictionary (a dictionary with pictures!) for the following terms: nebula, protostar, HertzsprungRussell Diagram, red dwarf, blue supergiant, Main Sequence, white dwarf, black hole, neutron star,
supernova, hydrostatic equilibrium, fusion, planetary nebula, nova, red giant, spectral class
Activity Description
A. Life Cycle of Stars (Background Information and Lab Report). Print out lab report and answer questions.
PDF files available on Mr. Jennings’ Home Page.
B. Spectral Classification of Stars I (Background Information and Lab Report). Print out lab report and
answer questions. PDF files available on Mr. Jennings’ Home Page.
C. Stellar Evolution Model. Construct a physical model of the life cycle of a sun-like star. Include detailed
descriptions of chemical composition at each stage. The physical model could take many forms:
 Computer simulation
 Diorama
 Poster
 Other (negotiate with Mr. Jennings here; no PowerPoints or WORD docs please).
D. High-Mass Stellar Evolution. Write an essay that describes the evolution of a massive star (> 20 Msun)
from the moment it uses up all its hydrogen until the moment of core collapse. What is the final product of the
death of such a massive star? What is important about the final product?
E. Spectroscopy. Write a short essay describing how the spectrum of a star be used to:
 determine chemical composition
 surface temperature
 magnetic field
 density
 radial velocity (how fast the star is moving towards Earth or away from Earth)
 estimate how fast the star is rotating? What kinds of star have large rotation speeds - and why?
F. Stellar Ejecta. Write a short essay that answers the following
questions:
 What is the object in this image?
 How did this object form?
 What would usually be found at the centre of these types of
objects?
Level 3
Activity Description
A.Properties of Planetary Nebulae. Visit
http://www.astro.washington.edu/courses/labs/clearinghouse/labs/ProppnShort/proppn.html
for instructions and questions. The ‘long axis’ mentioned in the activity refers to the longer width in the
nebula.
B. Hertzsprung-Russell Diagram Lab. Visit http://astro.unl.edu/naap/hr/hr.html. Do the following:
a. Read the Spectral Classification of Stars background material
(http://astro.unl.edu/naap/hr/hr_background1.html) and answer the questions in the Mini-Exercise.
Submit the answers.
b.
Read the Luminosity background material (http://astro.unl.edu/naap/hr/hr_background2.html) and
answer the questions using the Stellar Luminosity Calculator. Submit the answers.
c. Read the Hertsprung-Russell Diagram background material
(http://astro.unl.edu/naap/hr/hr_background3.html) and answer the following questions:
i. After who is the HR Diagram named?
ii. What is the Stefan-Boltzmann Law?
iii. What is the relationship between mass of a Main Sequence star and luminosity?
iv. What are Cepheid Variable stars and where do they lie on the HR diagram? Give
two examples of Cepheid Variable stars.
d. Open the HR Diagram Explorer and answer the questions on the HR Diagram Explorer worksheet*
(available from Mr. Jennings).
C. Identifying Lines in the Solar Spectrum.
Visit (http://www.astro.washington.edu/courses/labs/clearinghouse/labs/Solarspec2/sunspec.html#table1)
D. Spectral Classification of Stars II.
Visit (http://www.astro.washington.edu/courses/labs/clearinghouse/labs/Spectclass/spectralclassweb.html)
E. Estimate Main-Sequence Life of Sun. Estimate the main-sequence lifetime of the Sun: i.e., how long the
Sun will burn hydrogen into helium in its core. Assume that the Sun was initially entirely composed of
hydrogen, and that the Sun's current mass was its mass before main-sequence burning. You will use some
known properties of the Sun, and the knowledge that the Sun fuses hydrogen into helium.
(i) From the internet, find the mass (in kg) and luminosity (in Watts) of the Sun.
(ii) The Sun's principal reaction is the proton-proton (p-p) chain reaction, in which 4 hydrogen atoms (protons)
are converted into a 4-He nucleus (alpha particle). Each p-p reaction releases 4.2x10-12 Joules of energy. Use
this number and the luminosity of the Sun to calculate how many p-p reactions must occur every second.
(iii) Now calculate the mass of hydrogen lost each second in the Sun, as hydrogen is converted into Helium.
In each p-p reaction, 4 protons are lost (you'll need to find the mass of the proton), and you know the number
of p-p reactions occurring every second from (ii).
(iv) Now you can make a rough estimate of the main-sequence lifetime of the Sun knowing the mass of the
Sun and the mass of hydrogen lost each second (assume the mass of the Sun was all Hydrogen at the start
of main-sequence burning).
(v) Compare this estimated main-sequence lifetime with more sophisticated calculations-- how close are you?
What assumptions made above might not be correct?
SHOW ALL WORK (FORMULAE & CALCULATIONS) FOR THIS PROBLEM.
F. Black Hole Essay. Write a short essay on black holes that answers the following questions:
(a) Describe the structure of a non-rotating black hole.
(b) How are rotating black holes different from non-rotating black holes?
(c) Briefly describe two observable effects of objects falling onto a black hole.
(d) Describe the following types of black holes: stellar-mass, supermassive and primordial.
(d) How are stellar-mass black holes detected and their masses inferred?
G. Mass-Luminosity Relation. A nearby star happens to be twice as massive as the Sun, and also twice as
large.
(a) What is its main sequence lifetime compared to that of the Sun?
(b) What is its surface temperature compared to the Sun? Use the Mass-Luminosity relation.
(c) What is the star's spectral type?
(d) How much hydrogen does it need to fuse into helium every second to support itself?
H. Supernova Essay. Write a short essay on supernovae that answers that following questions:
(a) What are the differences between Type Ia and II supernovae in terms of their: lightcurves, spectra,
location in galaxies, max brightness, progenitor stars, and formation mechanism?
(b) A supernova explosion is observed by astronomers in a nearby galaxy. What spectral line observations
can the astronomers perform to determine the type of supernova event this was?
(c) What is the property of SN type Ia that makes them special? Name one scientific result that has resulted
from making use of this property.
---------------------------------------------------------------------TEAR OFF-----------------------------------------------------------------------------Name:
Class Notes
Pictionary
Life Cycle of Stars
Spectral Classification of Stars I
Stellar Evolution Model
High-Mass Stellar Evolution
Spectroscopy
Stellar Ejecta
Comments:
Max. Grade Possible:
Grade Achieved:
Properties of Planetary Nebulae
Hertzsprung-Russell Diagram Lab
Identifying Lines in the Solar Spectrum
Spectral Classification of Stars II
Estimate Main-Sequence Life of Sun
Black Hole Essay
Mass-Luminosity Relation
Supernova Essay