Cepheid variable

High school (ages 12+)
Space & Astronomy

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Date:

Step 1 · Read the article

Open the article and read it at the level above. Then answer the questions below in your own words.

https://smallwhale.org/articles/cepheid-variable

Write what each word means, using the article.

Do not copy the article. Write two things you learned, the way you would explain them to a friend.

Answers below are taken from the article’s stored facts, so they match what the student read.

1. Who discovered Cepheid variable?Henrietta Swan Leavitt, 1912, based on observations in the Small Magellanic Cloud
2. What is the pulsation mechanism?Driven by the kappa mechanism involving helium ionization and de-ionization
3. What is the role in distance measurement?Primary standard candles for extragalactic distances, crucial for calibrating Type Ia supernovae
4. What is a Cepheid variable star?A Cepheid variable is a giant star that regularly gets brighter and dimmer, like a giant light bulb blinking in space.
5. Why do Cepheid stars blink?They blink because layers inside the star heat up and cool down, causing the star to expand and shrink in a steady rhythm.

Kappa Mechanism: An internal stellar process involving opacity changes that drives the pulsation of certain variable stars.
Absolute Magnitude: A measure of a star's intrinsic brightness, independent of its distance from Earth.
Inverse Square Law of Light: The principle stating that the apparent brightness of a light source decreases with the square of the distance.
Hubble Constant (H0): The rate at which the universe is expanding per unit distance.