1. Question 1: The CNO cycle, Review Quiz No. 13 :60 1.involves the fusion of Carbon, Nitrogen, and Oxygen into heavier elements. 2.involves the fission of Carbon, Nitrogen, and Oxygen into nuclei of Helium and Hydrogen. 3.involves the fusion of 4 Hydrogen nuclei into Helium. 4.involves the fission of Helium into 4 Hydrogen nuclei. 5.involves the fusion of Helium nuclei into Carbon, Nitrogen, and Oxygen nuclei.

2. Question 2: In a binary system consisting of an 0.5- solar-mass star and an 8-solar-mass star, the 0.5-solar-mass star is orbiting around … :45 1.the center of the 8-solar-mass star. 2.the center of the 0.5-solar-mass star. 3.the mid-point halfway between the two stars. 4.the center of mass, located rather close to the 0.5-solar-mass star. 5.the center of mass, located rather close to the 8-solar-mass star.

3. Question 3: In a binary system, you observe two stars orbiting each other with a period of 2 years at a distance of 4 AU from each other. If one of the stars has a mass of 1 solar mass, the other star must have a mass of … :45 1.1 solar mass. 2.2 solar masses. 3.15 solar masses. 4.16 solar masses. 5.Impossible to tell with the available information.

4. Question 4: In a spectroscopic binary, the parameters (P, a) are measured indirectly by observing :45 1.periodically shifting patterns of stellar absorption lines. 2.periodically shifting patterns of stellar emission lines. 3.periodically disappearing and re-appearing stellar absorption lines. 4.periodically disappearing and re-appearing stellar emission lines. 5.a pair of stars periodically eclipsing each other.