Download Review Questions for Exam #2

Review Questions for Exam #2
In order to figure out the mass of a star we
observe binary star systems and use Kepler’s 3rd
Law,
(M1 + M2) P2 = 4π2*a3/G
Discuss how we determine, P and a.
How do we solve for individual mass (like M1)
rather than (M1 + M2)?
• Sketch an H-R diagram. Label the axes and indicate
the direction of increase along each axis.
• Draw in the location of the main-sequence, super
giants (I) the giants (III) and the white dwarfs.
• On the main-sequence, indicate with an arrow the
direction of increasing mass.
• Given the arrow that you have drawn, how are
luminosity and mass related on the MS and why?
• Put a big “R” in the place where on the diagram
where the radii are the biggest. Put a “r” where the
radii are the smallest.
• Given the relation L = σT4(4πR2) explain why the “R”
and “r” are at the locations you have labeled
• Here is an image near the center of the Orion
nebula, a star forming region.
• Explain what is happening in this picture
• Explain how this is related to the process of
self-sustained star formation in the molecular
cloud.
Fe
• Discuss how the absorption lines form. What has to
be true about the electrons in order to create
absorption lines?
• What do the strength of the absorption lines depend
on?
• In the spectra below, the temperature is the same for
all three spectra. Why are the lines different
strengths?
Explain what is happening to the proto-star as it follows
the track below.
Explain this diagram
• What is going on at #1, #2, #3, #4?
• In #3 what is happening on the outside of the star?
Why?
#3
#4
#2
#1
• Explain why a high mass core cannot get
energy out of fusion of Iron.
• What happens to the core of a high mass star
when it becomes iron?
• How does it produce a supernova?
• Explain why a neutron star spins incredibly
fast.
• How do we know that neutron stars really do
spin rapidly?
• What objects show us that neutron stars spin
fast?
• How does this object work?