Module 4—The Birth, Life, and Death of Stars


Module 4 examines how stars are formed from the matter, or cosmic dust, of “empty” space and how they evolve, live, and eventually die. The mass of a star determines how long it lives and how violently it dies. Planet formation appears to be a common result of star formation, and exoplanets are just about everywhere.


Module 4 covers the following topics:

  • Between the stars: the interstellar medium
  • The birth of stars and planets
  • Stellar evolution


After successfully completing Module 4, you should be able to:

MO4.1     Describe the nature of the interstellar medium.

MO4.2     Explain how stars are born from cosmic dust and why planets are a likely by-product of star formation.

MO4.3     Describe the evolution of stars from main sequence to Red Giant and differentiate between the life cycles of low-mass, medium-mass, and high-mass stars.

MO4.4     Discuss the death of stars and differentiate between the fates of low-mass, medium-mass, and high-mass stars.

MO4.5     Explain how a supernova provides astronomers with information about the type of star involved and its ultimate fate.

Course objectives covered in this module include CO6, CO7


Textbook Readings

  • Chapters 20, 21, 22, and 23 in Fraknoi, Morrison, and Wolff, Astronomy

Other Required Reading



Module 4 has three activities. Please consult the Course Calendar for the due dates.

Icon imageDiscussion Forum 4

In Discussion Forum 4, post your response to the following discussion question. Reply to at least two classmates’ responses by the date indicated in the Course Calendar.

The search for planets elsewhere in our galaxy is one of the primary investigations in astronomy today. If you were to be involved in such a project, which characteristics of stars would you focus on as most likely to harbor planets? What types of strategies would you use to determine if planets did, in fact, orbit those stars? And what characteristics would be necessary for the likelihood of Earth-like planets around those stars? [MO4.1, MO4.2]

Icon imageWritten Assignment 4

Answer the following questions.

  1. Describe the process of star formation from the interstellar medium.
  2. Describe the evolution of stars from birth to death. Distinguish the differences in those processes for low-mass stars, medium-mass stars, and high-mass stars.
  3. Describe how and why stars eventually die. Explain the different endpoints of small, medium, and high-mass stars.
  4. Explain the differences between a nova and a supernova. How does a type Ia supernova differ from a type II supernova? How are gamma ray bursts related to supernovas?

The use of outside sources is optional, but you must provide citations and references in APA format for any sources you use, including the textbook. Lack of proper citations and references and/or poor grammar and spelling could result in a grade deduction of 5 to 15 points. [MO4.1, MO4.2, MO4.3, MO4.4, MO4.5]

Icon imageModule 4 Quiz

Take the Module 4 Quiz by the date indicated in the Course Calendar. The quiz consists of 10 to 15 multiple-choice items that assess concepts from the textbook readings.

You may take these quizzes multiple times for additional practice; the result of your most recent attempt will appear in your gradebook. [MO4.1, MO4.2, MO4.3, MO4.4, MO4.5]