HR Diagram Science Quiz
Spectral Class:
(Color)--Sun's Spectral Class = G2
Explain why we know that there are red giants and supergiants on the HR Diagram.
-Red Giants and Supergiants are both cold red stars that DO NOT FALL ON THE MAIN SEQUENCE TREND LINE. -Supergiants are significantly brighter than even red giants -Supergiants are significantly larger than normal red stars
What 4 properties does the HR Diagram use to classify stars?
1. Luminosity 2. Spectral Class (Color)--Sun-G2 3. Temperature 4. Absolute Magnitude--(How bright it appears because of its size)
What is the relationship between temperature/color and brightness in the HR Diagram?
1. Stars with a high temperature are blue and bright 2. Stars with a low temperature are red and dim
What 3 things determine how bright a star will appear from Earth?
1.Size of the Star 2.Temperature of Star. 3.Distance how far away the star is from Earth. OR Magnitude and Luminosity
How many TYPES of stars are shown on the HR Diagram?
4
What 2 things affect the Absolute Magnitude and/or Apparent Magnitude of a star?
Affected by temperature and Size
What affects the luminosity of a star:
As the size of a star increases, luminosity increases (Size & Temperature)
Why do stars with a high temperature die out faster?
Because they burn fuel faster
What color are stars with very high temperatures?
Blue
Which color of stars die out faster?
Blue stars
Describe a large star:
Burn fuel faster= die faster -Bright -Hot or Cold
Describe a small star:
Burn fuel slower =Live longer -Dim -Hot or Cold
Red Stars=
Cool
Describe a cool star:
Dim , live longer, burns slower
Which type of star is dimmer than the sun?
Dwarfs
How does a Red Giant Form?
Helium + Helium + Helium=Carbon
How does a Red SuperGiant Form?
Helium + Helium + Hydrogen =Carbon & Heavy Elements
Which type of stars have a shorter life time: High temperature stars, or low temperature stars?
High temperature Stars
Blue Stars=
Hot
Apparent Magnitude:
How bright a star appears from earth
Absolute Magnitude:
How bright a star is from a specific distance
How does Fusion form?
Hydrogen + Hydrogen=Helium--Release Energy
As a star changes color from red to blue, describe what happens to its surface temperature?
It gets Hotter
Explain what a Cepheid Variable Star is:
It's size & Brightness changes. As the star's size increases, temperature decreases.
Which type of stars have a longer life time: High temperature stars, or low temperature stars?
Low Temperature Stars
What color are stars with very low temperatures?
Red
What type of star has both a low luminosity and low temperature?
Red Dwarfs
What is the color order on the HR Diagram? (Cold to Hot)
Red, Orange, Yellow White, Teal/green, Blue
What are the 4 TYPES/GROUPS of stars:
Supergiants Dwarfs Giants Main Sequence
What is the relationship between luminosity and temperature for stars on the Main Sequence?
The brighter it is, the hotter it becomes. (If temperature increase, luminosity increases)
What is the relationship between temperature/color and expected lifetime? Which stars will die first and why?
The higher the temperature of a star, the shorter the lifetime.---Blue stars will die out more quickly because of their high temperatures. (Their fuel burns faster and they need more)
What determines the color of a star?
The star's temperature
Which of the following describes our Sun? (A,B,C) a. The Sun is a blue star with a high luminosity and extremely hot temperatures b. The sun is a yellow star, considered, to be average , and is the reference point for the luminosity chart c. The sun is a red, low temperature star with a low luminosity
b. The sun is a yellow star, considered, to be average , and is the reference point for the luminosity chart
Luminosity:
the brightness of a Star in comparison with that of the sun-- (Luminosity of Sun= 1)
