Download Data Tables - AlmaMiddleSchoolScience

Name________________________ Date___________ Hour _____
H-R DIAGRAM
Stars live and die on such a long time scale that humans often have a problem understanding
that a star is a like giant factory that is driven by gravity to fuse light elements like hydrogen under
heat and pressure into heavier atoms like helium and the other heavier elements of the periodic table.
At the cores of stars, hydrogen atoms are squished together under extreme heat and pressure to fuse
together to make larger atoms. In the process a small amount of matter is converted into large amounts
of radiation energy. (E=mc2) This radiation energy travels out from the core of the star into space.
A billionth of the sun’s radiation energy, (the sun is round and gives off energy in all directions)
travels to earth, passes through its five layered atmosphere and is absorbed by the chlorophyll in plant
leaves. Chlorophyll in the leaves combines carbon dioxide and water to store the radiation energy as
chemical bonds in a sugar molecule. If the plant is buried under water and decays for millions of years
under heat and pressure, the oxygen atoms found in the sugar molecules are cooked off and only the
hydrocarbons remain to form the fossil fuels of coal, oil and if it is heated even more, natural gas.
The Hertzsprung - Russell diagram
Enjar Hertzsprung and Henry Russell were working on the same problem on different sides of the
Atlantic Ocean at the same time. Each took the known brightness and temperatures of stars cataloged
by Anne Cannon and plotted them to a graph sheet. Three quarters of a million stars were plotted to
see if there were patterns. Four main groups were discovered: “Super Giants”, “Giants”, “Main
Sequence” and “White Dwarfs”.
Stars on the main sequence generate energy by
converting (via fusion) hydrogen into helium. As stars
use up their hydrogen fuel, they evolve off the main
sequence into the giant or supergiant phase. A star will
move from left to right -- from hot to cool -- as it ages.
When astronomers actually measure stars in the sky and
plot them on the HR diagram, they find about 90% on the
main sequence, (Most main sequence stars are red
dwarfs) about 10% in the giant area on the right, and
very few in the area between.
DIRECTIONS:
1. Using the graph “paper” supplied in this lab, plot the 30 stars listed in Data Tables 1 & 2.
2. Use one colored pencil to plot the temperature and brightness data for each of the 15 nearest stars.
Make a small dot of the same color for each of the stars listed and give each dot its appropriate ID
number.
3. Using a different color pencil, plot the temperature and brightness for each of the 15 brightest
stars. Again, use the same color for ALL the dots and label each with its ID number.
1
How does our sun compare to other stars?
Data Table 1
15 Stars nearest Earth in the color__________
ID#
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Star
Sun
Proxima Centuri
Alpha Centuri A
Alpha Centuri B
Barnard’s Star
Wolf 359
Lalande 21185
Sirius A
Sirius B
Luyten 726-8A
Luyten 726-8B
Ross 154
Ross 248
Epsilon Eridani
Ross 128
Temperature
(°C)
5600
5800
4200
2800
2700
2600
13200
13000
10700
2700
12700
12000
2700
4500
2800
Brightness
(Sun = +2)
+2
+2.5
-2
-5.5
-6
-7
-13.5
+4
+12
-11.5
-12
-12
-4
-3
-9
Distance from
Earth in Light Years
0.000 02
4.3
4.3
4.3
5.9
7.6
8.1
8.8
8.7
8.9
8.9
9.4
10.3
10.7
10.8
Data Table 2
15 Brightest Stars in Northern Hemisphere in the color________
ID#
Star
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
Aldebaran
Altair
Antares
Arcturus
Betelgeuse
Capella
Deneb
Fomalhaut
Pollux
Procyon
Regulus
Rigel
Sirius
Spica
Vega
Temperature
(°C)
4200
6000
3400
4500
16200
5900
9900
13000
4900
8500
20000
11880
18000
21000
17700
Brightness
(Sun = +2)
+9
+8
+7
+8
+14
+13
+14
+13
+8
+2
+9
+4
+6
+8
+5
Distance from the
Earth in light years
68
16
424
36
587
42
1630
23
35
11
84
800
8.8
260
26
2
TEMPERATURE VS. BRIGHTNESS OF 30 SELECTED STARS
The O B A F G K M at the top of the page can be remembered in order with the mnemonic sentence- Oh Be
A Fine Girl (or guy), Kiss Me.
In short, the hottest stars are O class stars and the coolest, yet are still undergoing
fusion, stars are M class stars. The letter label applies to all stars to the right of the letter to
the next letter. The second half of the star classification is how bright a star is. These
numbers show the brightness of a star in comparison to our sun.
Observe your graph. Can you place the stars in four distinct groupings? Please draw a circle around
the four groups and label each group as Super Giants, Giants, Main Sequence, or White Dwarf, as you
feel the name best applies. Use your graphs to answer #1-5.
Open the following links and click on the two pictures and use the information to answer the five
questions that follow.
http://aspire.cosmic-ray.org/labs/star_life/hr_interactive.html
http://astrosun2.astro.cornell.edu/academics/courses//astro201/sun_hrtrack.htm Sun’s path on HR diagram
3
1. Explain the Hertzsprung-Russell (H-R) diagram. The H-R Diagram compares stars
brightness to its temperature into four groups, with most stars falling into the main
sequence followed by the grouping of giants, super giants and white
______________________.
2. Explain how you can infer the temperature, life span, and mass of a star from its
color.
A star’s color tells you its _______________, from that and its size you can infer its
place in the life cycle of a star.
3. Use the H-R diagram to explain the life cycles of stars.
H-R diagrams illustrates how a star is born from a hydrogen nebula, becomes a main
sequence star and then a supergiant or giant finally dying as a black dwarf, neutron
star or pulsar or ___________ hole
4. Explain the balance between
fusion and gravity in a star
(equilibrium).
A star’s is made from hydrogen
that is squished together to form
helium in the cores of stars by
gravity causing heat and
________________________.
5. Compare the evolution paths of
low-, moderate-, and high-mass
(1, 10 & 40 mass) stars using the
H-R diagram.
1m*- A low mass star will live
billions or trillions of years and
spend most of its life on the main sequence.
10m*- A medium mass star will live for about 10 million years, and then swell into a
red giant and then die as _____________________________ star or pulsar.
40m*- A high mass star only lives for millions of years, then swells into a giant or
super giant and then makes heavy elements out of light elements, and dies as a
supernova that make black _________________
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Extra challenge!
6. What color is Polaris? ________________________________________________________
7. What temperature is Rigel? ____________________________________________________
8. How bright (luminous) is Sirius? ________________________________________________
9. List three stars on the Main Sequence: ____________________________________________
10. How is Alpha Centauri different from the Sun? ____________________________________
11. Is Procyon B an old star or a young star? _________________________________________
12. As luminosity increases on the Main Sequence, the temperature of the stars _____________.
13. Which stage of life is the Sun currently in? ________________________________________
14. What is the largest named star on the chart? _______________________________________
15. As star color changes from red to white to blue, star temperature _______________________
16. What color are the small stars on the Main Sequence? _______________________________
17. What is the name of the brightest white dwarf? ____________________________________
18. Name two supergiants: ________________________________________________________
5
This is a picture of some of the stars you graphed. Are your star ID numbers in about the right place?
Think of this as a partial answer key!
If the original star is very massive,
(10 times the mass of the Sun) the
collapse will be extremely rapid
and the release of energy so great
the star explodes. Its outer parts,
now rich in heavy elements, will
be blown far out into interstellar
space, where they will be visible
as a supernova remnant. After
100,000 years or so the debris will
have mingled with the interstellar
gas, enriching it with heavy
elements. From this gas a new
generation of stars will be born.
FYI: More information
http://www.astro.ubc.ca/~scharein/a311/Sim/hr/HR
diagram.html HR Diagram Simulator
Australia Telescope Outreach and Education - Stellar Evolution Links
http://outreach.atnf.csiro.au/education/senior/astrophysics/stellarevolution_links.html
Mathtools.net-some models: http://www.mathtools.net/Java/Astronomy/
NASA students 5-8: http://www.nasa.gov/audience/forstudents/5-8/index.html
http://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml
http://81science.com/81Science.com/History_of_the_Universe.html
Phases of the inner planets (interactive Java
animation)
Retrograde motion (interactive Java animation)
Kepler's Laws (interactive Java animation)
Cratering (Java applet)
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