Astronomy Chpt. 3 Assignment – Flashcards
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Two stars both have parallaxes of 0.023, but start A has apparent magnitude +2.3 while star B is magnitude +7.3. Which statement is true?
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Star A is both 100 x brighter and more luminous than star B
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Compared to type A0 star, type A9 star is
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cooler
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On the H-R diagram, white dwarfs sirius B and procyon B lie
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At the lower left
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On the H-R diagram, the sun lies
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About the middle of the main sequence
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The doppler shift is used to find
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Spectroscopic binaries
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A star's absolute magnitude is its apparent brightness as seen from
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10 parasecs distance
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Which of these stars would be the hottest?
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B0
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What physical property of a star does the spectral type measure?
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Temperature
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The ________ magnitude of a star depends on its luminosity and distance from us
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Apparent
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A star has a parallax of 0.01 arc seconds. Its distance is
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100 parasecs
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Studies of a stars position made on the same calendar date over subsequent years yield ________
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Proper motions
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In the H-R diagram, what are the two most important types of data platted?
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Spectral classes and absolute magnitudes
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To find the distance of nearby stars, we use their parallaxes obtained over ______ month intervals
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Six
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Compared to the size of the sun, stars of all types range from
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0.01 to over 1,000 solar radii
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How much brighter will a 4th magnitude star appear than a 6th magnitude star?
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6.25 times
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A parasec is about 3.3 light years
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True
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A parasec is slightly more than 200,000 AU
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True
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If binary is detected by periodic shifts in its spectral lines it is a ______ binary
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Spectroscopic
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Binary stars separated enough to be resolved in a telescope are called
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Visual binaries
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Stars of the main sequences, like our own, are all converting ______ to helium
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Hydrogen
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A stars ______ parallax is found by using the spectral lines to estimate the spectral class and luminosity of distant stars
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Spectroscopic
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On the H-R diagram, red supergiants like Betelgeuse lie
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At the top left
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What can be said with certainty about a red star and a blue star?
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The blue star has a greater proper motion than the red star
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Which statement about stellar motion is incorrect?
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You must know the parallax to get the transverse velocity
