Stellar parallax is used to measure the distances of stars. The angle of stellar parallax gets larger as the length of the baseline increases. The size and distance relationship of the Sun and the next nearest star can be modeled using two golf balls separated by 100 km. A star's proper motion is its true motion in space combined with its radial motion towards or away from Earth.

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2. Question 1 Stellar parallax is used to measure the 1) sizes of stars. 2) distances of stars. 3) temperatures of stars. 4) radial velocity of stars. 5) brightness of stars.

3. Question 1 Stellar parallax is used to measure the 1) sizes of stars. 2) distances of stars. 3) temperatures of stars. 4) radial velocity of stars. 5) brightness of stars. Parallax can be used to measure distances to stars accurately to about 200 parsecs (650 light years).

4. Question 2 The angle of stellar parallax for a star gets larger as the 1) distance to the star increases. 2) size of the star increases. 3) size of the telescope increases. 4) length of the baseline increases. 5) wavelength of light increases.

5. Question 2 The angle of stellar parallax for a star gets larger as the 1) distance to the star increases. 2) size of the star increases. 3) size of the telescope increases. 4) length of the baseline increases. 5) wavelength of light increases. Astronomers typically make observations of nearby stars 6 months apart, making the baseline distance equal to 2 AU (Astronomical Units).

6. Question 3 You can best model the size and distance relationship of our Sun & the next nearest star using 1) a tennis ball here, and one on the Moon. 2) two beach balls separated by 100 city blocks. 3) two grains of sand 100 light years apart. 4) two golf balls 100 km apart. 5) two baseballs 100 yards apart.

7. Question 3 You can best model the size and distance relationship of our Sun & the next nearest star using 1) a tennis ball here, and one on the Moon. 2) two beach balls separated by 100 city blocks. 3) two grains of sand 100 light years apart. 4) two golf balls 100 km apart. 5) two baseballs 100 yards apart. The Sun is about one million miles in diameter. The next nearest star is about 25 million times further away.

8. Question 4 A star’s proper motion is its 1) true motion in space. 2) apparent shift as we view from opposite sides of Earth’s orbit every six months. 3) annual apparent motion across the sky. 4) motion towards or away from us, revealed by Doppler shifts. 5) orbital motion around the Galaxy.

9. Question 4 A star’s proper motion is its 1) true motion in space. 2) apparent shift as we view from opposite sides of Earth’s orbit every six months. 3) annual apparent motion across the sky. 4) motion towards or away from us, revealed by Doppler shifts. 5) orbital motion around the Galaxy. A star’s “real space motion” combines its apparent proper motion with its radial motion towards or away from Earth.

10. Question 5 In the stellar magnitude system invented by Hipparchus, a smaller magnitude indicates a _____ star. 1) brighter 2) hotter 3) cooler 4) fainter 5) more distant

11. Question 5 In the stellar magnitude system invented by Hipparchus, a smaller magnitude indicates a _____ star. 1) brighter 2) hotter 3) cooler 4) fainter 5) more distant

12. Question 6 A star’s apparent magnitude is a number used to describe how our eyes measure its 1) distance. 2) temperature. 3) brightness. 4) absolute luminosity. 5) radial velocity.

13. Question 6 A star’s apparent magnitude is a number used to describe how our eyes measure its 1) distance. 2) temperature. 3) brightness. 4) absolute luminosity. 5) radial velocity.

14. Question 7 The absolute magnitude of a star is its brightness as seen from a distance of 1) one million km. 2) one astronomical unit. 3) one light year. 4) ten parsecs. 5) ten light years.

15. Question 7 The absolute magnitude of a star is its brightness as seen from a distance of 1) one million km. 2) one astronomical unit. 3) one light year. 4) ten parsecs. 5) ten light years. Astronomers use a distance of 10 parsecs (about 32 light years) as a standard for specifying and comparing the brightnesses of stars.

16. Question 8 Which of the following quantities do you need in order to calculate a star’s luminosity? 1) apparent brightness (flux) 2) Doppler shift of spectral lines 3) color of the star 4) distance to the star 5) 1 and 4

17. Question 8 1) apparent brightness (flux) 2) Doppler shift of spectral lines 3) color of the star 4) distance to the star 5) 1 and 4 Which of the following quantities do you need in order to calculate a star’s luminosity?

18. Question 9 What are the two most important intrinsic properties for classifying stars? 1) distance and surface temperature 2) luminosity and surface temperature 3) distance and luminosity 4) mass and age 5) distance and color

19. Question 9 What are the two most important intrinsic properties for classifying stars? 1) distance and surface temperature 2) luminosity and surface temperature 3) distance and luminosity 4) mass and age 5) distance and color The H-R diagram plots stars based on their luminosities and surface temperatures.

20. Question 10 Wien’s law tells us that the hotter an object, the _____ the peak wavelength of its emitted light. 1) longer 2) more green 3) heavier 4) shorter 5) more constant

21. Question 10 Wien’s law tells us that the hotter an object, the _____ the peak wavelength of its emitted light. 1) longer 2) more green 3) heavier 4) shorter 5) more constant Wien’s law states that hotter stars appear more blue in color, and cooler stars appear more red in color.

22. Question 11 We estimate the surface temperature of a star by using 1) its color. 2) the pattern of absorption lines in its spectrum. 3) Wien’s law. 4) differences in brightness as measured through Red and Blue filters. 5) All of the above.

23. Question 11 We estimate the surface temperature of a star by using 1) its color. 2) the pattern of absorption lines in its spectrum. 3) Wien’s law. 4) differences in brightness as measured through Red and Blue filters. 5) All of the above.

24. Question 12 Which spectral classification type corresponds to a star like the Sun? 1) O 2) A 3) F 4) G 5) M

25. Question 12 1) O 2) A 3) F 4) G 5) M The OBAFGKM classification scheme is based on absorption lines. Which spectral classification type corresponds to a star like the Sun?

26. Question 13 The key difference between the spectra of B stars and G stars is 1) B stars show strong Hydrogen lines; G stars weaker Hydrogen lines. 2) B stars show few metal lines; G stars show many. 3) B stars have no metal atoms. 4) G stars have no Hydrogen atoms. 5) Both 1 and 2 are true.

27. Question 13 The original OBAFGKM sequence was arranged alphabetically by the strength of Hydrogen absorption lines. B stars had strong hydrogen lines, G stars had weak lines. The key difference between the spectra of B stars and G stars is 1) B stars show strong Hydrogen lines; G stars weaker Hydrogen lines. 2) B stars show few metal lines; G stars show many. 3) B stars have no metal atoms. 4) G stars have no Hydrogen atoms. 5) Both 1 and 2 are true.

28. Question 14 Astronomers can estimate the size of a star using 1) apparent brightness. 2) direct observation of diameter. 3) temperature. 4) distance to the star. 5) 1, 2, and 3 are all true.

29. Question 14 Astronomers can estimate the size of a star using 1) apparent brightness. 2) direct observation of diameter. 3) temperature. 4) distance to the star. 5) 1, 2, and 3 are all true. Brightness and temperature are used to plot the star on an H-R diagram, and indicate its approximate size. Some stars are large enough to measure directly.

30. Question 15 Eclipsing binary stars are very useful for determining the 1) ages of stars. 2) absolute luminosities of stars. 3) masses of stars. 4) distances to stars. 5) rotation rates of stars.

31. Question 15 Eclipsing binary stars are very useful for determining the 1) ages of stars. 2) absolute luminosities of stars. 3) masses of stars. 4) distances to stars. 5) rotation rates of stars. Analysis of the lightcurve of an eclipsing binary star system can reveal the masses of the stars.

32. Question 16 What is the single most important characteristic in determining the course of a star’s evolution? 1) density 2) absolute brightness 3) distance 4) surface temperature 5) mass

33. Question 16 What is the single most important characteristic in determining the course of a star’s evolution? 1) density 2) absolute brightness 3) distance 4) surface temperature 5) mass A star’s mass determines how fast it forms, its luminosity on the main sequence, how long it will shine, and its ultimate fate.