Exam 12: Characterizing Stars

The star $\zeta$ Canis Majoris has an absolute magnitude of -2.4 and a spectral class of B2. Using Figures 12-7 and 12-8 from the text, how would Canis Majoris be classified?

Listed below are parameters of stars that astronomers obtained from their measurements. Which of these conclusions is obviously NOT possible, based on the positions of these stars on the Hertzsprung-Russell diagram in Figure 12-8 in the text? (L_s and R_s are the luminosity and radius of the Sun, respectively.)

Three stars have the following absolute (M) and apparent (m) magnitudes: Star A: M = 1.8 m = 3.8 Star B: M = 2.5 m = 9.5 Star C: M = 7.6 m = 15.1 Which star is farthest away from Earth?

Measurements indicate that a certain star has a very high luminosity (100,000 times as bright as the Sun) and yet is relatively cool (3500 K). How can this be?

Classifying stars by spectral type is the same as categorizing them by

How many stars (other than the Sun) have an angle of parallax greater than 1 second of arc?

Using the Hertzsprung-Russell diagram in Figure 12-7 in the text, and the mass-luminosity relationship for main-sequence stars shown in Figure 12-15 in the text, which of these lists is the correct sequence of stars in INCREASING order of mass?

Suppose that two identical stars (they have the same total light output) are located so that star A is at a distance of 5 pc, and star B is at a distance of 25 pc from Earth. How will star B appear, compared with star A?

In the Hertzsprung-Russell diagram in Figure 12-7 in the text, which of these lists is the correct sequence of stars in order of INCREASING temperature?

Stellar parallax as small as 0.01 arcsec can be measured using telescopes on Earth. To what distance does this measurement correspond in space?

The difference in the brightness of a star as seen through two different colored filters, for example, blue and yellow, is directly related to which stellar property?

f a nearby star shows a parallax of 0.5 arcsec (when Earth moves through 1 au, by definition), what is its distance from Earth, in light-years?

In what fundamental way do humans (and many other animals) utilize parallax for the measurement of distance?

What particular and very important phenomenon frequently occurs in binary star systems where the stars are very close together?

A star that is 100 pc distant from Earth has an apparent magnitude of m = +2.5. What is its absolute magnitude?

A star of apparent magnitude +1 appears _____ than a star of apparent magnitude +2.

The spectral class of the star Enif is K2, while that of the Sun is G2. Which of these conclusions can be drawn about Enif from this information?

A star's absolute magnitude and its apparent magnitude have the same numerical value. How far is this star from Earth?

An eclipsing binary system consists of

The relative brightness of a star as seen in Earth's sky is called