HR Diagram Science Quiz

Questions and Answers

What 4 properties does the HR Diagram use to classify stars?

Temperature (correct)

Absolute Magnitude (correct)

Luminosity (correct)

Spectral Class (Color) (correct)

How many TYPES of stars are shown on the HR Diagram?

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?

Dwarfs Signup and view all the answers

What is the relationship between luminosity and temperature for stars on the Main Sequence?

The brighter it is, the hotter it becomes. Signup and view all the answers

What determines the color of a star?

The star's temperature Signup and view all the answers

Which of the following describes our Sun? (Select the correct answer)

The Sun is a yellow star and is the reference point for the luminosity chart Signup and view all the answers

Explain what a Cepheid Variable Star is:

Its size and brightness changes. Signup and view all the answers

What type of star has both a low luminosity and low temperature?

Red Dwarfs Signup and view all the answers

What color are stars with very low temperatures?

Red Signup and view all the answers

What color are stars with very high temperatures?

Blue Signup and view all the answers

How does Fusion form?

Hydrogen + Hydrogen = Helium, releasing energy. Signup and view all the answers

How does a Red Giant form?

Helium + Helium + Helium = Carbon Signup and view all the answers

How does a Red Supergiant form?

Helium + Helium + Hydrogen = Carbon & Heavy Elements Signup and view all the answers

What is the relationship between temperature/color and brightness in the HR Diagram?

Stars with a high temperature are blue and bright Signup and view all the answers

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. Signup and view all the answers

Which color of stars die out faster?

Blue stars Signup and view all the answers

Why do stars with a high temperature die out faster?

Because they burn fuel faster Signup and view all the answers

Which type of stars have a longer lifetime: high temperature stars or low temperature stars?

Low temperature stars Signup and view all the answers

Which type of stars have a shorter lifetime: high temperature stars or low temperature stars?

High temperature stars Signup and view all the answers

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. Signup and view all the answers

What are the 4 TYPES/GROUPS of stars?

Main Sequence Signup and view all the answers

Describe a cool star:

Dim, live longer, burns slower Signup and view all the answers

What is luminosity?

The brightness of a star in comparison with that of the sun. Signup and view all the answers

What is absolute magnitude?

How bright a star is from a specific distance Signup and view all the answers

What is apparent magnitude?

How bright a star appears from Earth Signup and view all the answers

What 2 things affect the absolute magnitude and/or apparent magnitude of a star?

Temperature and size Signup and view all the answers

Describe a large star:

Burn fuel faster = die faster; bright; hot or cold Signup and view all the answers

Describe a small star:

Burn fuel slower = live longer; dim; hot or cold Signup and view all the answers

Red Stars =

Cool Signup and view all the answers

Blue Stars =

Hot Signup and view all the answers

What is spectral class?

The classification of a star based on its color, with the sun's spectral class being G2. Signup and view all the answers

What affects the luminosity of a star?

Size and temperature Signup and view all the answers

What 3 things determine how bright a star will appear from Earth?

Size of the star, temperature of the star, distance from Earth. Signup and view all the answers

What is the color order on the HR Diagram from cold to hot?

Red, Orange, Yellow, White, Teal/Green, Blue Signup and view all the answers

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!