Questions and Answers
What 4 properties does the HR Diagram use to classify stars?
How many TYPES of stars are shown on the HR Diagram?
4
As a star changes color from red to blue, what happens to its surface temperature?
It gets hotter
Which type of star is dimmer than the sun?
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What is the relationship between luminosity and temperature for stars on the Main Sequence?
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What determines the color of a star?
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Which of the following describes our Sun? (Select the correct answer)
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Explain what a Cepheid Variable Star is:
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What type of star has both a low luminosity and low temperature?
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What color are stars with very low temperatures?
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What color are stars with very high temperatures?
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How does Fusion form?
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How does a Red Giant form?
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How does a Red Supergiant form?
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What is the relationship between temperature/color and brightness in the HR Diagram?
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What is the relationship between temperature/color and expected lifetime? Which stars will die first and why?
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Which color of stars die out faster?
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Why do stars with a high temperature die out faster?
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Which type of stars have a longer lifetime: high temperature stars or low temperature stars?
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Which type of stars have a shorter lifetime: high temperature stars or low temperature stars?
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Explain why we know that there are red giants and supergiants on the HR Diagram.
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What are the 4 TYPES/GROUPS of stars?
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Describe a cool star:
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What is luminosity?
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What is absolute magnitude?
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What is apparent magnitude?
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What 2 things affect the absolute magnitude and/or apparent magnitude of a star?
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Describe a large star:
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Describe a small star:
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Red Stars =
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Blue Stars =
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What is spectral class?
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What affects the luminosity of a star?
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What 3 things determine how bright a star will appear from Earth?
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What is the color order on the HR Diagram from cold to hot?
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Study Notes
HR Diagram Overview
- Classifies stars using four properties: Luminosity, Spectral Class (Color), Temperature, and Absolute Magnitude.
- Total of four types of stars represented on the HR Diagram: Supergiants, Giants, Dwarfs, Main Sequence.
Star Color and Temperature
- Stars change color from red (cooler) to blue (hotter) as their surface temperature increases.
- Low temperature stars appear red, while high temperature stars appear blue.
Star Classification
- The Sun is classified as a yellow star, considered average and serves as the luminosity reference point.
- Dwarf stars are dimmer than the Sun.
- Cepheid Variable Stars experience changes in size and brightness, with an inverse relationship between size and temperature.
Luminosity and Temperature Relationship
- Brightness and temperature positively correlate: as a star's temperature increases, its luminosity also increases.
- High temperature stars (blue) have shorter lifespans due to faster fuel consumption, while low temperature stars (red) live longer.
Lifecycle of Stars
- Fusion occurs when hydrogen combines to form helium, releasing energy.
- Red Giants form from the fusion of helium into carbon, whereas Red Supergiants involve the fusion of helium and hydrogen into carbon and heavy elements.
Magnitude Definitions
- Absolute Magnitude refers to brightness from a specific distance; Apparent Magnitude refers to how bright a star appears from Earth.
- Both magnitudes are influenced by a star's size and temperature.
Star Characteristics
- Large stars burn fuel faster and die sooner, while small stars burn fuel slower and live longer.
- A cool star is described as dim and long-lived due to its slower fuel consumption.
Spectral Classification
- Spectral Class, denoted by the color, is categorized with the Sun labeled as G2 within the classification system.
HR Diagram Color Order
- The color order from coldest to hottest stars is: Red, Orange, Yellow, White, Teal/Green, Blue.
Location on HR Diagram
- Red Giants and Supergiants do not align with the Main Sequence trend line and are significantly larger and brighter than typical stars.
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Description
Test your knowledge of the HR diagram with this engaging quiz. Explore key properties used to classify stars, learn about different types of stars, and understand how a star's color relates to its surface temperature. Perfect for astronomy enthusiasts and students alike!