Exam 15: Surveying the Stars

The following questions refer to the sketch of the H-R diagram below.Please choose the best answer in each case,i.e. ,choice (a)refers to the entire main sequence,while (c)and (d)refer to only small parts of the main sequence.If choice (c)or (d)offers a better answer to a particular question than (a),use the best choice.You may use the same choice more than once. -Which group represents the most common type of stars?

Which of the following terms is given to a pair of stars that appear to change positions in the sky,indicating that they are orbiting one another?

Two stars,Betty and Wilma,are both on the main sequence.Betty is more luminous than Wilma.Which one has a hotter surface temperature? Which one is more massive? Which one is bigger? If they both formed at the same time,which one will evolve off the main sequence first?

You observe a star in the disk of the Milky Way,and you want to plot the star on an H-R diagram.You will need to determine all of the following,except the

Which cluster is the oldest?

On an H-R diagram,stellar radii

Suppose you measure the parallax angle for a particular star to be 0.1 arcsecond.The distance to this star is

The faintest star visible to the naked eye has an apparent visual magnitude of about

The sketch below shows groups of stars on the H-R diagram labeled (a)through (e).Note that (a)represents the entire main sequence while (c)and (d)represent only small parts of the main sequence. -Which group represents stars that are extremely bright and emit most of their radiation as ultraviolet light?

Suppose you see two main-sequence stars of the same spectral type.Star 1 is dimmer in apparent brightness than Star 2 by a factor of 100.What can you conclude? (Neglect any effects that might be caused by interstellar dust and gas. )

What is the importance of Cepheid variables in astronomy?

Refer to the choices in the table for the following questions. -Which star has the largest radius?

Two stars have the same spectral type.Star X is in luminosity class III,while Star Y is in luminosity class V.Therefore,Star X is larger in radius than Star Y.

Refer to the choices in the table for the following questions. -Which star has the lowest surface temperature?

The most distant stars we can measure stellar parallax for are approximately

Refer to the choices in the table for the following questions. -Which star looks bluest in color?

Refer to the choices in the table for the following questions. -Which star is the most distant?

Two stars both lie on the main sequence.Star X is spectral type A,while Star Y is spectral type G.Therefore,Star X is more massive than Star Y.

A star of spectral type G lives approximately how long on the main sequence?

On a Hertzsprung-Russell diagram,where would we find stars that have the largest radii?