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Questions and Answers

What do astronomers use to find out the size of a distant star?

Hertzsprung-Russell diagram, temperature, and luminosity (correct)

Spectroscopy and light curve analysis

Distance measurements and parallax

Stellar classification and mass determination

What does luminosity refer to in the context of stars?

The total energy a star radiates in one second (correct)

The color of a star as observed from Earth

The size of a star relative to other stars

The distance of a star from the Earth

Why is it difficult to find the size of a star directly?

Stars look like a point of light through telescopes (correct)

Stars are constantly changing in size

Stars emit dangerous radiation

Stars are too far away for accurate measurement

What is the relationship between temperature and luminosity of stars?

Astronomers discovered a basic relationship between them Signup and view all the answers

What does the Hertzsprung-Russell diagram help determine about stars?

Size and position in the lifecycle Signup and view all the answers

Why can't we measure the size of a star with a regular ruler?

Stars are far away and look like points of light Signup and view all the answers

What is the primary challenge in finding the size of a distant star?

Stars look like a point of light through telescopes Signup and view all the answers

What does the Hertzsprung-Russell (H-R) diagram plot?

Star's luminosity vs. surface temperature Signup and view all the answers

Why do cool, bright giants and supergiants appear in the upper right region of the H-R diagram?

They are cool and luminous at the same time, requiring huge size to be very luminous Signup and view all the answers

What are the majority of stars, including our sun and red dwarfs, called on the H-R diagram?

Main-sequence stars Signup and view all the answers

Why do hot stars in the lower left corner of the H-R diagram have low luminosities?

They are small in size Signup and view all the answers

What is the relationship between a star's temperature and its luminosity on the H-R diagram?

A star with high temperature and high luminosity is larger in size Signup and view all the answers

What does the main sequence on the H-R diagram represent?

Where approximately 90% of stars lie, including our sun and red dwarfs Signup and view all the answers

What characteristic places a star in the main sequence on the H-R diagram?

Having characteristics similar to our sun and red dwarfs Signup and view all the answers

Why are giant stars called red giants?

They have a reddish color due to their cooler temperatures Signup and view all the answers