Section 14.A - Discover of Galaxies and uses of Cepheid Variable Stars Flashcards
1
Q
Recall it used to be thought all galaxies were just small nebulae inside the Milky Way, so they were called _____
A
spiral nebulae
2
Q
Know the correct method by which we determined that spiral nebulae are in fact galaxies far outside our Milky Way galaxy (3)
A
- Find stars in those spiral nebulae
- then find distances to those stars
- and that gives distances to the spirals
3
Q
Recognize the definition of a “variable star.”
A
????
4
Q
Be able to pick which aspect of Cepheid variable stars tells you their true brightness
A
their pulsation period does
5
Q
Recognize how the period-luminosity relation works for Cepheid stars
A
slower the pulsation, brighter the Cepheid
6
Q
Realize Cepheids help us get the distances to other galaxies, because Cepheid stars _______
A
are so bright they can be seen that far.
