Download Study Guide for the 4TH Astronomy Exam

Study Guide for the 4TH Astronomy Exam
Stellar Evolution
The successful student will be able to…
1. Star Formation
a. Describe the physical characteristics of a giant molecular cloud
b. Identify the source of heating (energy production) in protostars
c. Explain why more low-mass K & M main sequence stars form rather than the high-mass O & B stars.
d. List the mass limits of stars and explain why these limits apply.
e. Describe the processes and stages of star formation from a giant molecular cloud to an open cluster.
f. Identify in a photograph the following objects: a GMC, Bok Globule, OB Association, HII region, Open
Cluster
g. Describe the t-Tauri wind.
h. Interpret the physical changes of a forming star on an HR diagram.
i. Identify and define the ZAMS line on an HR diagram.
j. Describe the relationship between OB associations and HII regions.
2. Main Sequence Stars
a. List or identify the luminosity, mass, radius, temperature, and lifetime of an O main sequence star, the
Sun and an M main sequence star.
b. State the impact of convection in the envelope of very low mass stars on the stars main sequence lifetime.
c. Describe or identify changes in a star during its main sequence lifetime.
3. Giant Stars
a. Describe how shell fusion in a star causes the star to become giants.
b. Identify the “ashes” of H-burning and He-burning
4. Mass loss and Death of Low-Mass Stars
a. Match the stage of the Sun’s future evolution with the mechanism of energy production in that stage.
b. Identify on an HR diagram the stage of the Sun’s evolution and its mechanism of energy production.
c. List in chronological order the mechanisms of energy production in Sun-like stars.
d. List in chronological order the stages of evolution in Sun-like stars.
e. Describe the relation between the Helium Flash and the creation of a planetary nebula.
f. Describe the components and characteristics of a planetary nebula.
g. Identify the characteristics of white dwarf stellar remnants.
5. Old age and Death of Massive Stars
a. List the differences in energy production between low-mass stars and high-mass stars.
b. Describe the interior structure of a high-mass star near the end of its lifetime.
c. Identify the types of stars that will experience a core-collapse (Type II) supernova.
d. Identify the composition of the core of a star about to experience a core-collapse (Type II) supernova.
e. Describe two reasons why type II supernova a very useful standard candles.
f. Describe the impact of supernovas on the chemical evolution of the universe.
6. Problems
a. Apply Wien’s Law to find the temperature of a star or its wavelength of maximum emission.
b. Use the Stefan-Boltzmann Law to determine the luminosity, radius or temperature of a star compared to
the Sun.
c. Calculate the density of a star or other spherical object.
d. Calculate the main sequence lifetime of a star.
e. Use the angular size formula to determine the distance, or size of an astronomical object.
f. Use t=d/v to solve problems related to the collapse or expansion of star-related objects