Chapter Introduction
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Interstellar dust illuminated by light emitted from the red giant star V838 Monocerotis, in the center of the image.Characterizing Stars
WHAT DO YOU THINK?
How near to us is the closest star other than the Sun?
How luminous is the Sun compared with other stars?
What colors are stars, and why do they have these colors?
Are brighter stars hotter than dimmer stars?
Compared to the Sun, what sizes are other stars?
Are most stars isolated from other stars, as the Sun is?
Answers to these questions appear in the text beside the corresponding numbers in the margins and at the end of the chapter.
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Astronomers are witnesses to literally billions of stars in various stages of evolution. Therefore, although we cannot see any one star go through more than a tiny fraction of the process, we can see stars in every stage of stellar evolution. By understanding the changes that stars undergo, we gain insight into our place in the cosmos. We begin our journey to the stars by learning the properties of stars that astronomers used to develop models of why stars shine and how they evolve.
In this chapter you will discover
that the distances to many nearby stars can be measured directly, whereas the distances to farther ones are determined indirectly
the observed properties of stars on which astronomers base their models of stellar evolution
how astronomers analyze starlight to determine a star’s temperature and chemical composition
how the total energy emitted by stars and their surface temperatures are related
the different classes of stars
the variety and importance to astronomers of binary star systems
how astronomers calculate stellar masses