(15 Pts) ___ANSWER KEY ___Name 04 April, 2012 DUE

Home , List of smallest stars, Main sequence, Planetary nebula, Protostar, Red giant, Turnoff point

PROBLEM SET #6 (15 Pts) ______ANSWER KEY ______Name 04 April, 2012 DUE Fri, 13 April, 2012 ______ID #

1. A 1 solar mass star will most likely go through the following evolutionary stages. Arrange them in the correct evolutionary order (youngest to oldest): (4pts)

a) red giant ____C_____ (youngest)

b) white dwarf ____E______

c) protostar ____A_____

d) planetary nebula ____D______

e) main sequence ____B______(oldest)

2. Elements up to the atomic weight of uranium are built up in massive stars in what part of their evolutionary cycle ? (1pt)

( red giant, main sequence, protostar, white dwarf, supernova )

3. How long does the main sequence phase for a 1 solar mass star last ? (1pt)

( 1011 , 106 , 1010 , 104 , 102 ) years

4. The age of a cluster of stars can be judged by (2pts)

a) the turnoff point on the main sequence b) the total number of stars in the cluster c) the distance of the cluster from Earth d) the size of the cluster ______A____

5. The size of the Sun once it reaches the white dwarf stage will be about that of (1pt) ( Jupiter, Phobos, Charon, Saturn, Earth ).

6. The period of variability of a Cepheid variable star is directly related to which stellar parameter, which then provides a reliable method for the measurement of distances to stars ? (1pt)

( redshift , luminosity, surface temperature, magnetic field )

7. Which is the correct sequence for the following end-points of stellar evolution, in order of increasing main sequence stellar mass ? (2pts)

a) white dwarf, neutron star, black hole b) neutron star, black hole, white dwarf c) black hole, neutron star, white dwarf d) white dwarf, black hole, neutron star ______A______

8. What is the main by-product of “helium burning” in the core of red giant stars ?

( plutonium, hydrogen, carbon & oxygen, uranium ) (1pt)

9. The typical diameter of a neutron star of 2 solar masses is predicted to be approximately (1pt)

( 30 km 3,000 km 30,000 km 0.3 km )

10. The mass ejected as a shell or “remnant” of a supernova explosion of a massive star is what fraction of its pre-explosion mass ? (1pt)

a) less than one percent b) almost all (i.e greater than 90%) c) about one-tenth d) less than .01 percent ______B______