Exam 13: Taking the Measure of Stars

The blackbody spectra of a star with a temperature of 6000 K and a star with a temperature of 4000 K are shown below. An astronomer uses a telescope to observe each of these two stars in both the blue and red filters. The blue filter is centered at 450 nm, while the red filter is centered at 660 nm. For each of the two stars, state through which filter that star will be the brightest. Explain your answer.

When astronomers refer to "heavy elements," which elements are they talking about?

If we measure a star's luminosity and temperature, what other property of the star can we calculate? Explain how.

The spectral class of a star is related to its:

What is the main property of a main-sequence star that determines all its other properties?

On a typical H-R diagram, where are the stars with the largest radii located?

In a binary star system that contains stars with 2M _$\odot$ and 1M _$\odot$ , the velocity of the 2M _$\odot$ star will be _________ times the velocity of the 1M _$\odot$ star.

Which of the following properties would not be plotted on the horizontal axis of an H-R diagram?

Figure 1 -Figure 1 shows an H-R diagram, with five stars labeled A through E. Which star has the smallest radius?

What spectral class is the Sun?

The brightest stars in the sky also tend to be:

Which stars are the most common?

Stars X and Y are 5 AU apart from each other. Star X is four times as massive as star Y. The center of mass of this system is _________ AU away from star X and _________ AU away from star Y.

Explain how we can use spectroscopic parallax to determine the distance to a star farther away than a few hundred light-years.

Which of the following properties are NOT useful in determining the masses of stars in a typical binary system?

Stars A and B appear equally bright, but star A is twice as far away from us as star B. Which of the following is true?

Figure 1 -Figure 1 shows an H-R diagram, with five stars labeled A through E. Which star has the largest temperature?

Stars with a larger brightness must be closer to us than fainter stars.

What are the two main chemical elements that make up the Sun? How much of the mass of the Sun is composed of elements other than these two?

The faster-moving star in a binary is: