Which of the following is wrong? A. Tidal effects in a binary star system become more important when one or both stars become giant stars. B. There is no fusion occurring in the core of a low-mass red giant star. C. Gold (the element) is produced during the supernova explosions of high-mass stars. D. Suppose the star Betelgeuse were to become a supernova tomorrow, we'd see by naked eyes a cloud of gas expanding away from the position where Betelgeuse used to be. Over a period of a few weeks, this cloud would fill a large part of our sky.

When a mass is transferred through the inner Lagrangian point in a binary system toward a white dwarf, the material forms a rapidly growing whirlpool of material known as a(n)   a. accretion disk.   b. Lagrangian point.   c. Algol paradox.   d. planetary nebula.   e. supernova remnant.

15 On a Hertzsprung-Russell diagram, where on the main sequence would we find stars that have the greatest mass? A B D Lower right Upper right Upper left Lower left

1:Which star has been redshifted the most? 2:Which star is moving towards us the fastest? Star C Star D Star A Star B   3:The wavelength of this spectral feature is measured to be 600nm in the lab, and 609 in Star A.  What is the radial velocity of Star A? using km/s,

The average star spends what percentage of its life in the protostar stage?   a. 0.1%   b. 5%   c. 10%   d. 50%   e. 90%

Why is iron significant to understanding how a supernova occurs? A. Iron is the heaviest of all atomic nuclei, and thus no heavier elements can be made. B. Supernovae often leave behind neutron stars, which are made mostly of iron. C. The fusion of iron into uranium is the reaction that drives a supernova explosion. D. Iron cannot release energy either by fission or fusion.

For each statement concerning main sequence stars, select T True, F False, G Greater than, L Less than, or E Equal to. A) The surface temperature of a O type star is .... than a K type star. B) On the main sequence, the mass of a O type star is .... than a F type star. C) On the main sequence, a M type star's life is .... than a G type star. D) The surface temperature of our Sun is .... than the surface temperature of Sirius. E) When stars start hydrogen burning, thier mass determines where they are on the main sequence. F) Based on the relative lifes of M and G type stars we expect the number of M stars to be .... than the number of G type stars.

Based on what you know about main-sequence stars, select all of the correct statements from the following list. 1. Since the interiors of stars cannot be observed, there are no theories about their structure. 2. More massive stars are hotter and brighter. 3. The weight of a star must be balanced by internal pressure. 4. More massive stars live longer; they take longer to use up all their energy. 5. Stars change position on the main sequence throughout their lives. 6. Outward energy flow in a star is by conduction only.

A turnoff point corresponding to the youngest star cluster would occur at what spectral classification?   a. B   b. A   c. F   d. G

The mass-luminosity relation describes the mathematical relationship between luminosity and mass for main sequence stars.  It describes how a star with a mass of 4 M⊙ would have a luminosity of ______ L⊙. If a star has a radius 1/2 that of the Sun and a temperature 4 that of the Sun, how many times higher is the star's luminosity than that of the Sun? (If it is smaller by a factor of 8, you would write 0.125 because 1/8=0.125) If a star has a radius 2 times larger than the Sun's and a luminosity 1/4th that of the Sun, how many times higher is the star's temperature than that of the Sun? (If it is smaller by a factor of 8, you would write 0.125 because 1/8=0.125) If a star has a surface temperature 2 times lower than the Sun's and a luminosity the same as the Sun, how many times larger is the star than the Sun? (If it is smaller by a factor of 8, you would write 0.125 because 1/8=0.125)