Name ______Period ______

Stellar Properties: Mass and Lifespan

Consider 2 stars: Proxima Centauri and Vega.

·  Proxima Centauri has a mass of 0.12 solar masses

·  Vega has a mass of 2.6 solar masses

1. Which star contains more hydrogen to fuse into helium?______

2. PREDICT: Which star will run out of hydrogen first and become a red giant first?______

Compare Proxima Centauri and Vega to the following types of cars:

·  Car A is a 2 door coupe that gets 90 miles per gallon and has a 10 gallon tank for gas.

·  Car B is a SUV that gets 2 miles per gallon and has a 60 gallon tank.

3. Which car holds more fuel? ______

4. If both set out on a journey with a full tank of gas, which would run out of gas first? ______

5. Which car puts out more power? ______

6. Select which of the 2 stars listed above is more like Car A and which is more like Car B. Give 3 reasons for your choices. In your answer be sure to include and discuss power, fuel and size.

Proxima Centauri is like Car ______because:
Vega is like Car ______because:

7. Which star is more luminous? (1)______

8. Fill in this chart about the relationship between Luminosity and lifetime.(2)

Luminosity / Lifetime (Longer, shorter)
Higher
Lower

9. Consider the Sun and Vega. Which star will spend more time on the main sequence? ______

How do you know?

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Suppose an immortal astronomer were able to watch 2 stars being born together. The astronomer notices that Star A leaves the main sequence after 4 billion years, becoming a red giant. Star B leaves the main sequence after 10 billion years becoming a red giant.

10. Which star was more luminous during its time on the main sequence? ______

11. Which star was more massive? ______

12. Fill in the chart below about temperature of main sequence stars and color.

Color / Temperature
(hotter or cooler) / Luminosity
(higher or lower)
bluer
redder

13. What conclusion can you draw between the color of a star and its lifetime on the main sequence? (Be sure to give as many reasons as you can for your conclusion)