Question 15 [3 pts]: The accepted ordering for spectral classes among astronomers is OBAFGKM. You may have learned the classes with the phrase "Oh, be a fine girl/guy, kiss me." Why do the classes appear in this order?
Why do you think astronomers decided to reorder the spectral classes instead of just redefining what the letters meant (that is, changing what a class "A" star was)?
Conclusion question [5 pts]: Do you think a spectrum for a star will change as it ages? Explain why you think what you do.