Category: 1. The Stars: A Celestial Census

Learning Objectives By the end of this section, you will be able to: In this chapter and Analyzing Starlight, we described some of the characteristics by which we might classify stars and how those are measured. These ideas are summarized in Table 18.2. We have also given an example of a relationship between two of these characteristics…

Learning Objectives By the end of this section, you will be able to: It is easy to measure the diameter of the Sun. Its angular diameter—that is, its apparent size on the sky—is about 1/2°. If we know the angle the Sun takes up in the sky and how far away it is, we can…

Learning Objectives By the end of this section, you will be able to: The mass of a star—how much material it contains—is one of its most important characteristics. If we know a star’s mass, as we shall see, we can estimate how long it will shine and what its ultimate fate will be. Yet the…

Learning Objectives By the end of this section, you will be able to: Before we can make our own survey, we need to agree on a unit of distance appropriate to the objects we are studying. The stars are all so far away that kilometers (and even astronomical units) would be very cumbersome to use;…

How do stars form? How long do they live? And how do they die? Stop and think how hard it is to answer these questions. Stars live such a long time that nothing much can be gained from staring at one for a human lifetime. To discover how stars evolve from birth to death, it…