Variable Stars

 How much do you know about astronomy? How about variable stars?

Today we have challenging questions based on the article “Variable Stars” by Stella Kafka and Elizabeth O. Waagen in the Observer’s Handbook 2019.

I created five questions that could be answered without reading this chapter.

You have up to five minutes to complete the challenge today.

Begin now. Do your best.

ASTRONOMY CHALLENGE

  1. What do we call stars that change in brightness over time?

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  1. Mira, omicron Ceti, is a long period variable that is not fusing hydrogen into helium in its core. In what area of the HR Diagram will Mira be located?

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  1. Two main types of variable stars are 1. Intrinsic variables, where the change in brightness is due to changes within a single star, and what other?

  1. What specific kind of variable stars provided the key to the size of the Milky Way Galaxy?

  2. What specific kind of cataclysmic variables gives us clues about the distance to far-away galaxies?

OK, pencils down. Scroll down for directions for checking your answers.

Please read directions below:

Step 1: Please contribute to one of these charities linked below. If you are a winner and contribute, please ask recipient to notify me of the amount so I might match the first $100.

Michael J. Fox Foundation for Parkinson’s Researchfullsizeoutput_13f0

https://www.michaeljfox.org/

Click on “Get Involved”

Guilford County Animal Shelter

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               Look under “Donate to the Animal Shelter.”

 

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Guilford Senior Resources

http://senior-resources-guilford.org/

Look under “You Can Help”

Jo Cline Memorial Endowment

https://www.gtcc.edu/community-engagement/cline-observatory/support-the-observatory-jo-cline.php

Step 2: Check your written answers to the answers below. If your answer is correct, give it a check mark.

Step 3: If your answer is wrong, put a small X.

Step 4: If you think my answer is questionable, write yourself a note, do the research and let me know if I’ve erred. Thanks in advance,

You are welcome to play with us during the next live broadcast of

“Let’s talk astronomy” this coming Monday beginning at 8 am eastern US time on Periscope.

Periscope is a live video streaming app for Android and iOS available in the App Store.

On Monday, April 29, 2019, our Astronomy Challenge was about interplanetary dust.

The questions are given above, the correct answers and the winners are given below.

Congratulations to all winners and thank-you to all participants.

Play the Astronomy Challenge live on Periscope’s “ Let’s talk astronomy” 8 am (Eastern US time) on Mondays.

Correct Answers……..Periscope Winners:

  1. What do we call stars that change in brightness over time? ANSWER: variable …….@niceguy467: The star Mira in the constellation of the sea-monster, Cetus, is a good example of pulsating variable.

  1. Mira, omicron Ceti, is a long period variable that is not fusing hydrogen into helium in its core. In what area of the HR Diagram will Mira be located?   ANSWER: Giant ……@niceguy467: After fusion stops in core, a shell of hydrogen around the helium core begins to fuse. Since this shell is closer to the surface, the pressure makes the stars swell-up, becoming brighter, larger and cooler.

  1. Two main types of variable stars are 1. Intrinsic variables, where the change in brightness is due to changes within a single star, and what other? ANSWER: extrinsic, in which changes are due to interaction of multiple stars………@Pircano:   Mira, the variable mentioned in the previous question is an example of intrinsic variable. Algol, aka beta Persei, is extrinsic variable, Algol is actually a pair of eclipsing stars.

  1. What specific kind of variable stars provided the key to the size of the Milky Way Galaxy? ANSWER: Cepheids……@speear40: Henrietta Leavitt observed the pattern in the variation revealed their Absolute Magnitudes. I recommend George Johnson’s book Miss Leavitt’s Stars (W.W. Norton & Company, 2005)

  2. What specific kind of cataclysmic variables gives us clues about the distance to far-away galaxies?    ANSWER: Supernova,….@Pircano: visit the simulation at NAAP Astronomy “Supernova Light Curve Fitting Explorer” at

https://astro.unl.edu/naap/distance/animations/snCurveExplorer.html

Next challenge: May issue of Sky & Telescope

If you find a mistake, please let me know.

Thanks goes out to all participants,

and

Congratulations to everyone who got one right.


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