Stellar parallax measurements are used in astronomy to determine which of the following properties of stars?

The brightness a star would have if it were at 10 pc from Earth is called its

Measurements of a binary star system are required to determine what property of stars?

A star with which of the following apparent magnitudes appears brightest from Earth?

A star of what spectral class has the strongest (darkest) H_α line? (Hint: See Figure 10-5.)

Describe how the parallax method of finding a star’s distance is similar to the binocular (two-eye) vision of animals.

What is stellar parallax?

How do astronomers use stellar parallax to measure the distances to stars?

Why do stellar parallax measurements work only with relatively nearby stars?

What is the difference between apparent magnitude and absolute magnitude?

Briefly describe how you would determine the absolute magnitude of a nearby star.

What does a star’s luminosity measure?

How is the magnitude scale “backward” from what common sense dictates?

Does the star Betelgeuse, whose apparent magnitude is m = +0.5, look brighter or dimmer to us than the star Pollux, whose apparent magnitude is m = +1.1?

How and why is the spectrum of a star related to its surface temperature?

What is the primary chemical component of most stars?

A star of which spectral type has the strongest Na I absorption lines? At approximately what wavelength is this line normally found? (Hint: See Figure 10-5.)

Why does a G2 star have many more absorption lines than a B0 star?

Draw an H-R diagram and sketch the regions occupied by main-sequence stars, giants, supergiants, and white dwarfs. Briefly discuss the different ways you could have labeled the axes of your graph.

To test your understanding of the H-R diagram, do Interactive Exercise 11.1 on the assigned Web site. You can print out your answers, if required.

How can observations of a visual binary lead to information about the masses of its stars?

What is a radial-velocity curve? What kinds of stellar systems exhibit such curves?

What is the difference between a single-line and a double-line spectroscopic binary?

What is meant by the light curve of an eclipsing binary? What sorts of information can be determined from such a light curve?

What is the mass–luminosity relationship? To what kind of stars does it apply?

Referring to Figure 10-7:

What is the inverse-square law? Use it to explain why a headlight on a car can appear brighter than a star, even though the headlight emits far less light energy per second.

Explain how sailors on a ship traveling parallel to a coastline at a known speed can use parallax angle measurements to determine the distance to the shore.

Sketch the radial-velocity curve of a binary whose stars are moving in nearly circular orbits that are (a) perpendicular and (b) parallel to our line of sight.

Sketch the light curve of an eclipsing binary whose stars are moving along highly elongated orbits with the major axis of the orbits (a) pointed toward Earth and (b) perpendicular to our line of sight.

Discuss the advantages and disadvantages of measuring stellar parallax from a space telescope at the distance of Jupiter from the Sun compared to the same measurements made from Earth’s surface.

How does a star’s rotation affect the appearance of its spectral lines? Hint: Assume we are looking at the star from above its equator. Then, at every instant, half of the spinning star is approaching Earth, while the other half is receding. Consider the resulting Doppler shift in the spectral lines.

Of all the spectral classes of stars (O, B, A, F, G, K, M), which is least common?

Comparing them as if they were all the same distance from us, which of the following statements most accurately describes the Sun’s luminosity relative to other stars?

What colors are the hottest and coolest stars?

If a star is a red giant, how does its surface temperature compare to that of the Sun?