Julian Date: 2459027.16
2019-2020: CLXX
THE DAILY ASTRONOMER
Friday, July 3, 2020
Remote Planetarium 58: Week 12 Quiz
Would you believe we have just barely scratched the surface? Honestly, we would be flattering ourselves to even make that assertion. To actually do justice to each Remote Planetarium topic, we'd have to post a book, not an article. Moreover, we would need volumes just to keep everyone apprised of what is discovered every week. Such is the exponential science of astronomy. Knowing that a long trek still awaits us might exhilarate some and dismay others. As the adage goes, "The physicist learns more and more about less and less. The astronomer learned less and less about more and more." Then again, wouldn't life lose a little of its luster were everything to be precisely amassed and cataloged?
Today's quiz covers the three topics discussed this week: penumbral lunar eclipses, extrinsic variables and Cepheid variables. The good news about having a truncated week is that we're posting fifteen questions instead of twenty.
1. One of the lunar eclipses in Saros Cycle 149 will occur on August 17, 2092. When will the following Saros 149 lunar eclipse happen?
a. August 17, 2099
b. August 23, 2101
c. August 26, 2105
d. August 29, 2110
2. What is the penumbra?
a. the outer part of Earth's shadow
b. the inner part of Earth's shadow
c. the center of Earth's shadow
d. none of the above
3. On June 6, 2096, Lunar Saros Cycle 151 will begin. Based ONLY on information contained within that sentence, which statement(s) do you know must be true?
a. the eclipse will occur at or around the moon's descending node
b. the eclipse will be a partial penumbral eclipse
c. the next Lunar Saros Cycle 151 eclipse will occur around mid-June in 2114.
d. the eclipse will last four hours
Questions 4 -5 pertain to the image above.
4. Observers in Portland, Maine in the year 2489 will see how much of the eclipse that will happen on April 16th?
a. none of it
b. all of it
c. the eclipse will be in progress when the moon rises
d. the eclipse will be in progress when the moon sets.
5. Based on information contained within this image, which of the following statement(s) must be true?
a. the next eclipse in this series will occur in late April 2507
b. the next eclipse in this Saros cycle will be of longer duration
c. the zenith Sun position will be at a higher latitude during the next eclipse in this Saros cycle
d. none of the above.
6. Which of the following are types of extrinsic variable stars?
a. rotating variable stars
b. eclipsing binary stars
c. Cepheid variables
d. RR Lyrae variables
7. An Algol variable is what type of variable star?
a. rotating
b. eclipsing binary
c. Cepheid
d. RR Lyrae
8. The image above shows the change in Algol's brightness over time. This graph is actually called Algol's _________________
a. light curve
b. magnitude diagram
c. brightness spectrum
d. all of the above
9. Why aren't all binary stars eclipsing binaries?
a. because the star system has to be aligned with Earth in such a way so that the stars block each other during each revolution.
b. all stars are eclipsing binaries from our perspective. The brightness difference is so slight for most of these that we don't notice them.
c. in order to be an eclipsing binary star, the system has to have an additional component star
d. none of the above.
10. Which of the following statements about rotating variable stars is/are true?
a. their brightness could vary because of darker regions along the photosphere
b. their brightness could vary because of their ellipsoidal shape
c. their brightness could vary because of doubly ionized helium in their interiors.
d. none of the above.
11. Which of the following is/are type(s) of intrinsic variables?
a. pulsating
b. rotating
c. cataclysmic
d. eclipsing binary
12. How many different types of Cepheid variables have been identified?
a. 1
b. 2
c. 3
d. 4
13. What mechanism is believed to be responsible for Cepheid variability?
a. doubly ionized helium
b. core iron reserves
c. dark spots on the photosphere
d. none of the above
14. Why would a star's brightness change because of pulsations?
a. the change in size and temperature affects the luminosity, or energy output
b. because as the star expands, its mass increases and therefore increases the luminosity
c. as the outer layers contract, the fusion reactions in the core accelerate, increasing the luminosity
d. none of the above.
15. The longer a Cepheid's variability period, the _____________ the Cepheid.
a. more luminous
b. less luminous
c. older
d. younger