HW#24: pg. 442-443 Rev 7 – 9; CST 7 – 9
Rev 7 – 9
7. Why do some stars have very few hydrogen lines in their spectra?
8. What information is needed to plot a star on the H-R diagram?
9. What is the main sequence? What basic property of a star determines where it lies on the main sequence?
CST 7 – 9
7. Cool stars can be very luminous if they are very (a) small; (b) hot; (c) large; (d) close to our solar system.
8. According to Figure 17.13 ("H-R Diagram of Well-known Stars"), Barnard's star must be (a) hotter; (b) larger; (c) closer to us; (d) bluer than Proxima Centauri.
9. Figure 17.15 ("H-R Diagram of Brightest Stars") shows Vega and Arcturus at approximately the same level on the vertical axis. This means that Arcturus must be (a) hotter than; (b) fainter than; (c) larger than; (d) of the same spectral class as Vega.