Chapter 1. Luminosity of Variable Stars

Question What is the luminosity of a Cepheid variable star with the longest possible pulsation period?

34iG+4XPjQG9U7/88845YycR0TExwSm+jgGTzkHTYE4+YyBOJK5p81pY+2vJvMMgNbHuZxlEB8iww+YuwGRDyhba/bVsdbP+zApKIpOCT2A= {"title":"selection","description":"All RR Lyrae variable stars are about the same luminosity, regardless of their pulsation period. Therefore, if we see a RR Lyrae variable, and we know how bright it actually looks, we can easily tell how far away it is. These are important stars to astronomers.","type":"correct","color":"#ffffff","code":"[{\"shape\":\"rect\",\"coords\":\"28,133,418,181\"}]"} {"title":"selection COPY","description":"Incorrect","type":"incorrect","color":"#ffffff","code":"[{\"shape\":\"rect\",\"coords\":\"31,182,421,237\"}]"} {"title":"selection COPY COPY","description":"Incorrect","type":"incorrect","color":"#ffffff","code":"[{\"shape\":\"rect\",\"coords\":\"32,245,422,305\"}]"} {"title":"selection COPY COPY COPY","description":"Incorrect","type":"incorrect","color":"#ffffff","code":"[{\"shape\":\"rect\",\"coords\":\"39,310,429,395\"}]"}

Question What is the luminosity of a Cepheid variable with a period of 5 days?

34iG+4XPjQG9U7/88845YycR0TExwSm+jgGTzkHTYE4+YyBOJK5p81pY+2vJvMMgNbHuZxlEB8iww+YuwGRDyhba/bVsdbP+zApKIpOCT2A= {"title":"selection","description":"Incorrect","type":"incorrect","color":"#ffffff","code":"[{\"shape\":\"rect\",\"coords\":\"28,133,418,181\"}]"} {"title":"selection COPY","description":"Cepheid variables vary in the pulsation period and their luminosities, but they do so in very predictable ways. These stars are also important to astronomers as they try to determine the distance to objects in the universe.","type":"correct","color":"#ffffff","code":"[{\"shape\":\"rect\",\"coords\":\"33,209,305,264\"}]"} {"title":"selection COPY COPY","description":"Incorrect","type":"incorrect","color":"#ffffff","code":"[{\"shape\":\"rect\",\"coords\":\"32,267,195,292\"}]"} {"title":"selection COPY COPY COPY","description":"Incorrect","type":"incorrect","color":"#ffffff","code":"[{\"shape\":\"rect\",\"coords\":\"39,310,140,331\"}]"}

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