Analyzing Starlight (Ch 17)

Which color star is likely to be the hottest?

• red

• green

• blue-violet

• yellow

When an astronomer measures a color index for a star, what is she measuring?

• what color the human eye see when people look at that star

• the difference between how bright a star looks at two different wavelength regions

• the total luminosity of the star in all parts of the electromagnetic spectrum

• the amount of hydrogen in the atmosphere of a star

Which of the following types of star has the coolest temperature?

• O

• A

• M

• F

The main reason stars do not all look alike is that the stars...

• are located in many different regions of the Milky Way

• have different temperatures

• are made of significantly different elements

• sometimes have atmospheres and sometimes do not

Spectral Classes are arranged in order of...

• decreasing temperature

• increasing mass

• increasing amount of hydrogen

• decreasing distance from us

The astronomer who created the official catalog of spectral classes that we use today was...

• Edwin Hubble

• Annie Jump Cannon

• Cecilia Payne

• Joseph Fraunhofer

Which of the following celestial objects has too little mass to qualify as a star?

• a brown dwarf

• the Sun

• an M-type dwarf

• an O-type star

How do astronomers measure the speed of a star?

• by seeing the luminosity of the star decrease as it moves away

• by measuring the diameter of a star

• by seeing the whole star become redder

• by looking at the Doppler shift in the lines of the star's spectrum

Imagine you are one million years in the future. Which of the following statements about the sky you would see in that future time is correct?

• all the stars and constellations would look exactly the same as they do now

• all the stars we can see in the sky today will have died in a million years

• because of proper motion, a number of the familiar constellations will look somewhat different in a million years

• at the present time, astronomers do not know enough about the universe to say what the sky might be like in a million years

How do astronomers identify a star that is rotating rapidly?

• stars that rotate show a large Doppler Shift to only the blue end of the spectrum

• stars that rotate have a much lower luminosity

• stars that rotate have much wider absorption lines in their spectra

• there is no way to tell if stars are rotating rapidly