Two stars of the same main sequence type have different spectra. What can we say about them?

• They are different sizes

• They have different chemical compositions

• They have different masses

• They have different effective temperature

O stars are ____ in color.

• Red-Yellow

• Green-Yellow

• Blue-White

• Brown

What is the Spectral Type of the Sun?

• A

• M

• Binary

• G

Which of the following is the same for all stars along a horizontal line in the HR-diagram?

• Color/ Temperature

• Mass

• Spectral Type

• Brightness/ Luminosity

Which of the following is constant along a vertical line in the HR-diagram?

• Brightness/ Luminosity

• Chemical Composition

• Color/ Temperature

• Radius

Given apparent magnitude and distance to a star, what can you determine about it?

• Luminosity

• Mass

• Color

• Chemical Composition

Which of the following sequences of spectral types places main sequence stars in order of increasing mass?

• F,G,K,M

• K,M,O,A

• O,B,A,F

• M,K,G,F

A star has a parallax of 0.001 arc seconds.  How far away is it in parsec?

• 1 pc

• 10 pc

• 0.01 pc

• 1000 pc

If a yellow spectral line in a star is Doppler shifted toward the orange part of the spectrum. The source is ____

• Moving towards you.

• Moving northward relative to you.

• Moving away from you.

• Moving only in the plane of the sky.

Why are binary stars so important to astronomers?

• Single stars are boring.

• They are the only way to directly measure the mass of stars.

• They are the only way to directly measure the radius of stars.

• They are the source of most elements heavier than Helium