Astronomy 322 Winter Quarter 2005 Second Test   Name____________________

1.(18pts) Given the following objects: 
a=50 solar mass main-sequence star, b=1 solar mass main-sequence star, 
c=1 solar mass white dwarf, d=0.1 solar mass main-sequence star,
e=0.05 solar mass star, f=2 solar mass neutron star. Describe the
internal structure of each (this includes the location of radiative,
convective zones, any nuclear fusion going on in the cores or shells and
the internal chemical composition of the material). 

a)






b)






c)






d)






e)






f)







2.(7pts) For the cluster B shown here:





a) estimate its age and explain how you
   reached your conclusion






b) Give the type of star and evolutionary stage of the regions labelled
C and D.

C =                                           D=










3(8 pts). What is the Schwarzchild radius (in km) of:

a) the earth:





b) a typical globular cluser: (be sure to state your assumption for the mass of
a typical cluster)






c) It has been speculated that globular clusters harbor massive black
holes in their centers. How would you go about proving or disproving this
idea?








4(8pts). Images of galactic nebulae taken in different colors reveal two
predominant colors - those that are bluish and those that are very red.

a) The blue ones are ____________ nebulae and the red are ______________ nebulae.

b) Explain the physical cause of these resulting colors.






c) Describe what the spectra of these two types of nebula would look like.









5.(15 pts) Briefly describe how you would determine the following.
Describe the observational technique (spectrum, CCD image) as well as
the calculation that must be done in each case.

a) the distance to the Pleides






b) if a binary system contains a black hole







c) if nuclear fusion is really going on in the sun






d) whether an unknown star is a Cepheid






e) the age of a globular cluster






6(5pts). For 3 stars with B-V=0 (T~10,000K), masses were found to be 16,
3.5 and 1 solar mass. Explain how it is possible to have three stars of
the same color with these different masses. State what kind of star each
would be.











7.(4 pts) Polaris has been known to pulsate as a Cepheid variable. Given
its apparent magnitude of 2.0 and its distance of 200 pc, determine its
normal period of pulsation. (The P-L relation can be expressed as
M = -2.80 log P - 1.43 where M is the absolute visual magnitude and P
is the period in days).











8.(8pts) A typical neutron star has a radius of 10 km and a temperature
near 1 million K.

a) What is its black body luminosity (in ergs/s and solar luminosity)?







b) At what wavelength does this luminosity peak? What portion of the
electromagnetic spectrum is this?








c) Is this all of the radiation that emerges from a neutron star? Why
or why not?