Some study topics for the third midterm exam
The readings to be covered by the third exam include:
Chapter 15
Chapter 16
Chapter 17
Chapter 18
Chapter 19
But not chapter 20.
Chapter 15
What powers the Sun? Why does the fusion of hydrogen into helium provide energy? How long can the Sun fuse hydrogen into helium in its center? What is the photosphere? What are granules? How does energy get from the inside of the Sun to the surface? What is a sunspot? Why are sunspots dark? What is the Maunder minimum?
Chapter 16
How is the parallax of a star in seconds of arc related to its distance in parsecs? How does the amount of light we get from a star diminish with increasing distance? What is the sequence of spectral types from hottest to coolest (Do not bother remembering exact temperatures, just the order)? What is an HR diagram? Be able to interpret an HR diagram so as to figure out which stars are brighter, cooler, bigger, etc.? What is the main sequence? Where do we find white dwarf stars and red giants in the HR diagram? Where do we find the highest and lowest mass main sequence stars? Where is the Sun in the HR diagram? How can we tell the age of a star cluster from its main sequence turnoff on the HR diagram?
Chapter 17
What is a protostar? How does a protostar get energy to shine? Where are protostars in the HR diagram? What is a giant molecular cloud? How does the main sequence lifetime of a star depend upon mass? Will our Sun become a red giant? What do we think will eventually happen to the Sun? What is a planetary nebula? How is the evolution of a high mass star different from that of a low mass star? Why is a high mass star set to become a type II supernova when its core has turned to iron? What was supernova 1987A? How do supernova explosions help build heavy elements and cycle them into the interstellar medium? What is the Cepheid period-luminosity relation?
Chapter 18
What is degeneracy? What keeps a white dwarf from collapsing? About how big are white dwarf stars and neutron stars? Why are more massive white dwarfs smaller than less massive ones? How massive can a white dwarf be? Can a white dwarf become a supernova? Where do neutron stars come from? What is a pulsar? What is a black hole? What can escape from inside the event horizon of a black hole? Why do we think that Cygnus X-1 might contain a black hole? What is a gamma ray burster?
Chapter 19
What do we think are the shape and size of the Milky Way Galaxy? What are the bulge, halo, disk, and spiral arms? In what part of the Galaxy do we find interstellar gas and dust? In what part of the Galaxy do we see ongoing star formation? Can we see the center of the Galaxy at visible light wavelengths? If not, how can we see it? What is
Sgr A*? Why do we think there is a black hole at the center of the Galaxy? How do stars in the disk and halo orbit the Galactic center? What is the evidence for the mysterious dark matter? What is a density wave?