|
1 | | A star’s parallax can reveal its distance. Stars with larger parallaxes are _______ . |
| | A) | farther away |
| | B) | closer |
| | C) | the same distance as other stars |
| | D) | This is a trick question. Parallax cannot be measured for stars! |
|
|
|
2 | | A star has a parallax of 0.04 arc seconds. What is its distance? |
| | A) | 4 light years. |
| | B) | 4 parsecs. |
| | C) | 25 light years. |
| | D) | 25 parsecs. |
|
|
|
3 | | A star radiates most strongly at 400 nm. What is its surface temperature? |
| | A) | 400 K. |
| | B) | 4000 K |
| | C) | 7500 K. |
| | D) | 75,000 K |
|
|
|
4 | | A 10th magnitude star is __ than a 5th magnitude star. |
| | A) | 2 times brighter |
| | B) | 2 times fainter |
| | C) | 100 times brighter |
| | D) | 100 times fainter |
|
|
|
5 | | Stars have dark lines in their spectra because |
| | A) | the cooler atoms in their surface layers absorb the radiation at some wavelengths. |
| | B) | they simply don't emit light at certain wavelengths. |
| | C) | magnetic fields in the Earth's atmosphere absorb the radiation at some wavelengths. |
| | D) | The statement is false. Stars have bright emission lines in their spectra, but no absorption lines. |
|
|
|
6 | | Which of the following stars is hottest? |
| | A) | an M star |
| | B) | an F star |
| | C) | a G star |
| | D) | an O star |
|
|
|
7 | | What distinguishes the spectral class of a star? |
| | A) | Its brightness. |
| | B) | The lines in its spectrum. |
| | C) | Its distance. |
| | D) | Its velocity. |
|
|
|
8 | | A binary star is a pair of stars that orbit around each other. By detecting this orbital motion, and using Kepler’s Laws and the Law of Gravitation, one can directly measure the stars' |
| | A) | temperatures. |
| | B) | luminosities. |
| | C) | masses. |
| | D) | distances. |
|
|
|
9 | | What is a spectroscopic binary? |
| | A) | A spectroscopic binary looks, to us on Earth, like a single star, but its spectrum shows double lines that shift. |
| | B) | A visual binary for which we have spectra of both stars. |
| | C) | A visual binary in which one or both stars have peculiar spectra. |
| | D) | A visual binary which is shown by its spectrum to be a single star. |
|
|
|
10 | | The H-R diagram is a plot of stars' |
| | A) | temperature vs. mass. |
| | B) | mass vs. luminosity. |
| | C) | luminosity vs. temperature. |
| | D) | mass vs. diameter. |
|
|
|
11 | | What is the main sequence? |
| | A) | A region of cool, luminous stars in the upper right corner of the H-R diagram. |
| | B) | A region of hot, dim stars in the lower left corner of the H-R diagram. |
| | C) | An approximately straight line on the H-R diagram along which 90% of stars lies. |
| | D) | The order in which spectral types are listed. |
|
|
|
12 | | A cool but very luminous star must have |
| | A) | a very large radius. |
| | B) | a very small radius. |
| | C) | a very small mass. |
| | D) | a very low velocity. |
|
|
|
13 | | Cooler, less luminous main sequence stars have |
| | A) | higher masses. |
| | B) | lower masses. |
| | C) | the same masses as hotter stars. |
| | D) | masses that vary widely |
|
|
|
14 | | The period of a variable star is the time it takes its light to vary from |
| | A) | minimum to maximum light. |
| | B) | maximum to minimum light. |
| | C) | maximum light to the subsequent maximum. |
| | D) | when it leaves the Main Sequence to when it becomes a white dwarf. |
|
|
|
15 | | Where are Red Giants on the HR diagram? |
| | A) | Upper left |
| | B) | Upper right. |
| | C) | Lower left |
| | D) | Lower right |
|
|