LECTURE 16, OCTOBER 26, 2010 ASTR 101, SECTION 3 INSTRUCTOR, JACK BRANDT 1ASTR 101-3, FALL 2010
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Question 4 A star’s proper motion is its a) true motion in space. b) apparent shift as we view from opposite sides of Earth’s orbit every six months. c) annual apparent motion across the sky. d) motion toward or away from us, revealed by Doppler shifts. e) orbital motion around the galaxy. 7ASTR 101-3, FALL 2010
Question 4 A star’s proper motion is its a) true motion in space. b) apparent shift as we view from opposite sides of Earth’s orbit every six months. c) annual apparent motion across the sky. d) motion toward or away from us, revealed by Doppler shifts. e) orbital motion around the galaxy. A star’s “real space motion” combines its apparent proper motion with its radial motion toward or away from Earth. 8ASTR 101-3, FALL 2010
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Question 8 Which of the following quantities do you need in order to calculate a star’s luminosity? a) apparent brightness (flux) b) Doppler shift of spectral lines c) color of the star d) distance to the star e) a and d 12ASTR 101-3, FALL 2010
Question 8 a) apparent brightness (flux) b) Doppler shift of spectral lines c) color of the star d) distance to the star e) a and d Which of the following quantities do you need in order to calculate a star’s luminosity? 13ASTR 101-3, FALL 2010
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Question 5 In the stellar magnitude system invented by Hipparchus, a smaller magnitude indicates a _____ star. a) brighter b) hotter c) cooler d) fainter e) more distant 15ASTR 101-3, FALL 2010
Question 5 In the stellar magnitude system invented by Hipparchus, a smaller magnitude indicates a _____ star. a) brighter b) hotter c) cooler d) fainter e) more distant 16ASTR 101-3, FALL 2010
Question 7 The absolute magnitude of a star is its brightness as seen from a distance of a) one million km. b) one Astronomical Unit. c) one light-year. d) ten parsecs. e) ten light-years. 17ASTR 101-3, FALL 2010
Question 7 The absolute magnitude of a star is its brightness as seen from a distance of a) one million km. b) one Astronomical Unit. c) one light-year. d) ten parsecs. e) 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. 18ASTR 101-3, FALL 2010
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Question 12 Which spectral classification type corresponds to a star like the Sun? a) O b) A c) F d) G e) M 24ASTR 101-3, FALL 2010
Question 12 a) O b) A c) F d) G e) M The OBAFGKM classification scheme is based on absorption lines. Which spectral classification type corresponds to a star like the Sun? 25ASTR 101-3, FALL 2010
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Question 9 What are the two most important intrinsic properties for classifying stars? a) distance and surface temperature b) luminosity and surface temperature c) distance and luminosity d) mass and age e) distance and color 33ASTR 101-3, FALL 2010
Question 9 What are the two most important intrinsic properties for classifying stars? a) distance and surface temperature b) luminosity and surface temperature c) distance and luminosity d) mass and age e) distance and color The H–R diagram plots stars based on their luminosities and surface temperatures. 34ASTR 101-3, FALL 2010
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Question 15 Eclipsing binary stars are very useful for determining the a) ages of stars. b) absolute luminosities of stars. c) masses of stars. d) distances to stars. e) rotation rates of stars. 43ASTR 101-3, FALL 2010
Question 15 Eclipsing binary stars are very useful for determining the a) ages of stars. b) absolute luminosities of stars. c) masses of stars. d) distances to stars. e) rotation rates of stars. Analysis of the lightcurve of an eclipsing binary star system can reveal the masses of the stars. 44ASTR 101-3, FALL 2010
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