Study Guide for 3RD Astronomy Exam

Study Guide for 3RD Astronomy Exam

Summer 2015

The Sun

List or identify the vital statistics of the Sun

Describe the Sun in terms of a 2-layer model

·  List or identify the core properties and function

·  List or identify the envelope properties and function

·  Describe the eventual fate of all stars

The Sun’s Source of Power

Describe, in an essay, how the Sun produces energy by

·  describing the Net proton-proton chain reaction,

·  defining the symbols in the reaction,

·  stating the origin of the symbols in the reaction,

·  describe the process of thermalization of gamma rays in the Sun and state its significance.

Stellar Nomenclature

Interpret stellar apparent magnitudes and their relationship to brightness

Interpret stellar absolute magnitudes and their relationship to luminosity

Solve problems relating to the relative brightness or luminosity of two stars given their m or M values.

Determine the hottest and coolest stars from a list of stars with their spectral types.

Interpret the luminosity class of a star by naming the luminosity class and identifying if the star is in the “adult” phase or the “nursing home” phase of its evolution.

Describe or identify how a parsec is defined.

Convert stellar distances between parsecs and light years.

Write or identify the definition of the stellar motion term “Proper Motion”

Describe or identify types of binary stars.

State or identify what additional information can be obtained from and eclipsing binaries besides the combined mass of the stars.

Properly label the axes of an HR diagram and identify the regions.

Utilize the HR to identify a star’s luminosity, temperature, radius (and mass if it is a main sequence star).

Star Formation

Describe the physical characteristics of a giant molecular cloud

Identify the source of heating (energy production) in proto-stars

Explain why more low-mass K & M main sequence stars form rather than the high-mass O & B stars.

List the mass limits of stars and explain why these limits apply.

Describe the processes and stages of star formation from a giant molecular cloud to an open cluster.

Identify in a photograph the following objects: a GMC, Bok Globule, OB Association, HII region, Open Cluster

Describe the t-Tauri wind.

Interpret the physical changes of a forming star on an HR diagram.

Identify and define the ZAMS line on an HR diagram.

Describe the relationship between OB associations and HII regions.

Main Sequence Stars

List or identify the luminosity, mass, radius, temperature, and lifetime of an O main sequence star, the Sun and an M main sequence star.

State the impact of convection in the envelope of very low mass stars on the stars main sequence lifetime.

Describe or identify changes in a star during its main sequence lifetime.

Giant Stars

Describe how shell fusion in a star causes the star to become giants.

Identify the “ashes” of H-burning and He-burning

Mass loss and Death of Low-Mass Stars

Match the stage of the Sun’s future evolution with the mechanism of energy production in that stage.

Identify on an HR diagram the stage of the Sun’s evolution and its mechanism of energy production.

List in chronological order the mechanisms of energy production in Sun-like stars.

List in chronological order the stages of evolution in Sun-like stars.

Describe the relation between the Helium Flash and the creation of a planetary nebula.

Describe the components and characteristics of a planetary nebula.

Identify the characteristics of white dwarf stellar remnants.

Old age and Death of Massive Stars

List the differences in energy production between low-mass stars and high-mass stars.

Describe the interior structure of a high-mass star near the end of its lifetime.

Identify the types of stars that will experience a core-collapse (Type II) supernova.

Identify the composition of the core of a star about to experience a core-collapse (Type II) supernova.

Describe two reasons why type II supernovas are very useful standard candles.

Describe the impact of supernovas on the chemical evolution of the universe.

Problems

Calculate stellar distances in parsecs or light years using the stellar parallax relation.

Use the Stefan-Boltzmann Law to determine the luminosity, radius or temperature of a star compared to the Sun.

Determine the combined mass of a binary star system.

Apply Wien’s Law to find the temperature of a star or its wavelength of maximum emission.

Calculate the main sequence lifetime of a star.