Astronomy Pop Quiz on Variable Stars

Hello again, ladies and gentlemen. Please get out a clean sheet of paper and a No. 2 pencil and prepare for today’s Astronomy Pop Quiz.

The topic today: Variable Stars

You have six minutes to complete the quiz. Begin now.


  1. Name the European who, in 1572, was the first to

    Screen Shot 2018-06-27 at 3.45.23 PM
    17th century illustration of the Hypothesis Tychonica, whereby the Sun, Moon and sphere of stars orbit the Earth, while the five known planets (Mercury, Venus, Mars, Jupiter and Saturn) orbit the Sun.

    document a new star, a “nova.”

  1. 150 years later, Edmund Halley in 1715 knew of how many variable stars?

  1. What star in the constellation Cetus is the first known periodic variable?

  1. What is the common name for the star in Perseus that dims almost a full magnitude every 2.9 days?

  1. (Answer should be within 1 day of the exact number.) How often does Delta Cephei pulsate?

  1. Who discovered the Cepheid variables’ period-luminosity law?

  1. With Leavitt’s discovery, what important feature of stars could we calculate?

  1. What letter of the alphabet was given as part of the designation of the first variable found in each constellation?

OK, pencils down. Let’s trade with a neighbor and check one another. Here are the correct answers and your “neighbor” who got the correct answer on my Periscope broadcast on June 25, from 8:00 am (eastern US) to 9:00.


Correct Answers……..Periscope Winners:

  1. Tycho Brahe…..… @trojan120: On Periscope, we discussed Tycho’s nose and his death, both, very interesting stories. Did you know he also came up with a different model of the solar system? Aristotle’s followers insisted on an earth-centered, or geo-centric model. Copernicus had suggested a Sun-centered model: heliocentric.  Tycho came up with an interesting blending of the two. Interesting but still wrong.

  1. six…….. @Jason00Jason:  After a century and a half, only a half-dozen variable stars had been discovered. Scientists thought variables must be very rare. That helps explain why the IAU thought reserving just nine variable star designations per constellation would be more than enough. (See # 8 below.)

  1. Mira….………@1Johnnyboy: This variable is very bright for a few weeks and then the rest of the year it fades from view without a telescope. Mira is a Spectral Type M star, cooler and less massive than our Sun. It appears to be further along its evolutionary path than our Sun; it’s a red Giant.

Screen Shot 2018-06-27 at 3.54.42 PM
Click here for a neat video.
  1. Algol…………….@mrfahad47: Beta Persei is sometimes referred to as “the demon star” or al ghoul. That became the name Algol.

  1. 4 days.……….. @Tophedu06: This variable is a Spectral Type F supergiant. Can you find its place on the HR Diagram? What would be the relative temperature and luminosity of a Type F supergiant?


  1. Henrietta Leavitt.……….. @1Johnnyboy: The longer the period, the brighter the Absolute Magnitude (M). Sometimes instead of using M , scientists might use “L” for Luminosity, the amount of radiation a star emits

  1. Distance to far-away stars.……….. @tiki: Scientists can observe the spectrum of a star and determine its Spectral Type. We can use the Inverse Square Law with the Absolute magnitude, along with the apparent magnitude, and calculate the distance to that star. Cepheids helped us calculate the size of the Milky Way Galaxy and our location in it. Cepheids also helped Edwin Hubble determine the distances to galaxies.

  1. ……….. @Jason00Jason: Thinking variable stars were rare (see #2 above) reserving nine designations for variables seemed adequate. First variable would be “R” as in “R Coronae Borealis.” The second variable star discovered in a constellation would be given “S” as in “S Geminorum.” Then T, and so on to Z as in Z Andromeda. That made nine designations.

         But scientists kept discovering variables, so they went to RR, then continued to RS and so on to RZ. Then SS, ST, and on to SZ and so forth until ZZ. Then they go to AA and go thru the whole sequence, skipping the letter J, up to and including QZ. And those pesky astronomers kept on discovering variables.

        So finally the next variable discovered in the constellation was named V335, and next V336 and so on. Phew!

Winners: make a contribution in the next 30 days to one of my charities listed on my blog and I will match your gift, up to $100. Tell the charity to contact me about your contribution.

Astronomy Pop Quiz topic: Variable Stars

Winners posted on June 27, 2018

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.

Winners on my live show astronomy-related trivia questions correct will qualify for:

  1. Eternal Glory (yea!)

  2. International Reknown, and…

          drum roll, please…….

  1. An opportunity to increase your impact on making the world a better place.

How to increase your impact:

  1. correctly answer a trivia question participating in the live Periscope broadcast.

  2. Make a contribution within 30 days of publication of the Leader Board to one of the charities listed on my blog. You can find the list of my charities on the page “Want to Show Support?” pull down menu found on the home page of my blog.

Link here.

  1. Have the charity contact me to tell me the amount of your gift, and I will match it up to $100.

On Monday, June 25, 2018, our Periscope Trivia Contest was about variable sstaras. The questions, the correct answers and the winners are given above. Congratulations to all winners and thank-you to all participants.

When you get the first correct answer to one of my questions, you are a winner. I usually have between five and ten trivia questions each Monday.

To the winners go Eternal Glory, World-wide declaration of their victories (on my blog), and an Opportunity to double their impact of making the world a better place.

You are welcome to join in the hour long fun most Mondays beginning around 8 am eastern time. With

Screen shot 2015-12-28 at 8.16.26 PM

Periscope you can watch an earlier trivia game broadcast or participate in the next live Astronomy Pop Quiz   Periscope is a social media app available in the App store.


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