Week 7 DQ's

Week 7 DQ's - Discussion Questions (Due on Saturday): 1)...

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Discussion Questions (Due on Saturday): 1) What are some types of variable stars? How do they provide proof that star evolution occurs? A variable star is any star that changes it’s brightness in a periodic way. Variable stars include many different kinds of star. Some variable stars are eclipsing binaries, but many other stars that expand and contract, heat and cool, and grow more luminous and less luminous because of internal process. A couple types of variable stars are Cepheid variable stars, they are supergiant or bright giant starts of spectral type F or G. Another related type of star would be the RR Lyrae stars, they pulsate with periods of less than a day and are fainter then the Cepheid’s. The first way that they provide proof that star evolution occurs is that there is a period- luminosity relation that connects the period of pulsation of a Cepheid to its luminosity. The longer-period Cepheid’s are about 40,000 times more luminous that the sun, while the shortest- period Cepheid’s are only a few hundred times more luminous than the sun. The second way
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Week 7 DQ's - Discussion Questions (Due on Saturday): 1)...

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