Materials: Planetarium Dome, HR Diagram, Colored Pencils

Name______Period______

Hertzsprung-Russell Diagram

Purpose: Use provided data and your own observations to identify the characteristics used to classify stars and place them on the H-R Diagram

Materials: Planetarium dome, HR diagram, colored pencils

Procedure:

1. Observe stars on dome andwrite apparent magnitude, color, distance, and spectral class on data table 7-1.

Table 7-1: Star Temperature and Luminosity
Star Name / # / Color / Spectral Type / Apparent
magnitude / Distance
(l.y.) / Temperature
(K) / Luminosity
(relative to sun) / Mass
(solar mass)
Rigel / 1 / 14 000 / 66 000 / 20
Betelgeuse / 2 / 3 500 / 12 000 / 20
Polaris / 3 / 6 500 / 1 000 / 6
Aldebaran / 4 / 4 000 / 100 / 1.7
Sun / 5 / 6 000 / 1 / 1
Regulus / 6 / 12 300 / 300 / 3.5
Vega / 7 / 9 700 / 60 / 2.3
Spica / 8 / 19 700 / 10 000 / 10
Procyon / 9 / 6530 / 7.3 / 1.4
Pollux / 10 / 4865 / 43 / 1.8
Sirius A / 11 / 10,000 / 25 / 2
Bellatrix / 12 / 22,000 / 6,400 / 8.4
Sirius B / 13 / x / x / x / 8.6 / 25,000 / .03 / 1
Tau Ceti / 14 / x / x / x / 12 / 5 000 / 0.50 / 0.8
Alpha Centauri B / 15 / x / x / x / 4.3 / 4 300 / 0.3 / 0.9
Barnard’s Star / 16 / x / x / x / 5.98 / 3 000 / 0.002 / .17
Procyon B / 17 / x / x / x / 11.5 / 7 740 / 0.01 / 0.6

1. On the final page of this packet, label each axis of the HR Diagram correctly (temperature or luminosity)
2. Using the data from table 7-1, plot the position of each star using its approximate temperature and luminosity by writing its number in the correct location on the H-R diagram
3. In the “COLOR” box at the bottom of your HR Diagram,shade in each temperature region of the with the correct star color, using the information on table 7-2 below.

Table 7-2 Star Temperature, Spectral Class, and Color
Star Temperature (oK) / Spectral Class / Star Color
Less than 3,600 / M / Red
3,6000 – 5,000 / K / Orange
5,000 - 6,000 / G / Yellow
6,000 – 7,500 / F / Yellow-White (pale yellow)
7,500 – 10,000 / A / White
10,000-28,000 / B / Blue-White (pale blue)
Greater than 28,000 / O / Blue

1. In bold letters, label the following regions of your HR diagram with the following terms:

White DwarfRed DwarfsGiants Main Sequence Supergiants

1. In the “SPECTRAL CLASS” box at the bottom of the HR diagram, write the spectral class that coincides with each temperature range, using table 7-2 above.

Analysis questions:

1. As stars change color from red to blue, what happens to its surface temperature?

2. A main sequence star that is 100 times more luminous than the sun most likely has a temperature of

______.

4. A main sequence star that has a luminosity of 10 is most likely to be what color? ______

5. Name a white dwarf star that you plotted on your HR diagram:

1. A massive star with a temperature of 20,000K and a luminosity of nearly 100,000 would be classified as what

type of star? ______

7. Our sun has a Luminosity of ______and a temperature of ______

8. Other than the sun, name two other Main Sequence stars that you plotted on your HR diagram:

9. Why do you think we could not observe stars #13-17 on the dome?

10. Compare the apparent magnitudes, luminosities, and distances for Pollux (#10) and Bellatrix (#12). Why does

Pollux appear brighter in the sky when Bellatrix is so much more luminous?

1. Label each axis
2. Plot the stars by number
3. Use colored pencils in the “color box” near the bottomto indicate the data shown on table 7-2
4. Label these regions of the diagram: White Dwarf, Red Dwarfs, Main Sequence,Giants, Supergiants
5. In the “Spectral Class” box, write the letters of spectral classes in the order that corresponds with each temperature.

HR Diagram