Download PowerPoint

Clicker
Questions
Chapter 10
Measuring the
Stars
Copyright © 2010 Pearson Education, Inc.
Question 1
Stellar parallax
is used to
measure the
Copyright © 2010 Pearson Education, Inc.
a) sizes of stars.
b) distances of stars.
c) temperatures of stars.
d) radial velocity of stars.
e) brightness of stars.
Question 1
Stellar parallax
is used to
measure the
a) sizes of stars.
b) distances of stars.
c) temperatures of stars.
d) radial velocity of stars.
e) brightness of stars.
Parallax can be used to measure
distances to stars accurately to about 200
parsecs (650 light-years).
Copyright © 2010 Pearson Education, Inc.
Question 2
The angle of
stellar parallax
for a star gets
larger as the
Copyright © 2010 Pearson Education, Inc.
a) distance to the star increases.
b) size of the star increases.
c) size of the telescope increases.
d) length of the baseline increases.
e) wavelength of light increases.
Question 2
The angle of
stellar parallax
for a star gets
larger as the
a) distance to the star increases.
b) size of the star increases.
c) size of the telescope increases.
d) length of the baseline increases.
e) wavelength of light increases.
Astronomers typically make
observations of nearby stars 6 months
apart, making the baseline distance
equal to 2 AU (Astronomical Units).
Copyright © 2010 Pearson Education, Inc.
Question 3
You can best model
the size and distance
relationship of our
Sun & the next
nearest star using
Copyright © 2010 Pearson Education, Inc.
a) a tennis ball here, and one on the
Moon.
b) two beach balls separated by 100
city blocks.
c) two grains of sand 100 light-years
apart.
d) two golf balls 100 km apart.
e) two baseballs 100 yards apart.
Question 3
You can best model
the size and distance
relationship of our
Sun & the next
nearest star using
a) a tennis ball here, and one on the
Moon.
b) two beach balls separated by 100
city blocks.
c) two grains of sand 100 light- years
apart.
d) two golf balls 100 km apart.
e) two baseballs 100 yards apart.
The Sun is about one million miles
in diameter.
The next nearest star is about 25
million times farther away.
Copyright © 2010 Pearson Education, Inc.
Question 4
A star’s proper
motion is its
Copyright © 2010 Pearson Education, Inc.
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.
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.
Copyright © 2010 Pearson Education, Inc.
Question 5
In the stellar magnitude
system invented by
Hipparchus, a smaller
magnitude indicates a
_____ star.
Copyright © 2010 Pearson Education, Inc.
a) brighter
b) hotter
c) cooler
d) fainter
e) more distant
Question 5
In the stellar magnitude
system invented by
Hipparchus, a smaller
magnitude indicates a
_____ star.
Copyright © 2010 Pearson Education, Inc.
a) brighter
b) hotter
c) cooler
d) fainter
e) more distant
Question 6
A star’s apparent
magnitude is a number
used to describe how
our eyes measure its
Copyright © 2010 Pearson Education, Inc.
a) distance.
b) temperature.
c) brightness.
d) absolute luminosity.
e) radial velocity.
Question 6
A star’s apparent
magnitude is a number
used to describe how
our eyes measure its
Copyright © 2010 Pearson Education, Inc.
a) distance.
b) temperature.
c) brightness.
d) absolute luminosity.
e) radial velocity.
Question 7
The absolute magnitude
of a star is its brightness
as seen from a distance
of
Copyright © 2010 Pearson Education, Inc.
a) one million km.
b) one Astronomical Unit.
c) one light-year.
d) ten parsecs.
e) ten light-years.
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.
Copyright © 2010 Pearson Education, Inc.
Question 8
Which of the following
quantities do you need
in order to calculate a
star’s luminosity?
Copyright © 2010 Pearson Education, Inc.
a) apparent brightness (flux)
b) Doppler shift of spectral
lines
c) color of the star
d) distance to the star
e) a and d
Question 8
Which of the following
quantities do you need
in order to calculate a
star’s luminosity?
Copyright © 2010 Pearson Education, Inc.
a) apparent brightness (flux)
b) Doppler shift of spectral
lines
c) color of the star
d) distance to the star
e) a and d
Question 9
What are the two
most important
intrinsic properties
for classifying stars?
Copyright © 2010 Pearson Education, Inc.
a) distance and surface temperature
b) luminosity and surface temperature
c) distance and luminosity
d) mass and age
e) distance and color
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.
Copyright © 2010 Pearson Education, Inc.
Question 10
Wien’s law tells us that the
hotter an object, the _____
the peak wavelength of its
emitted light.
Copyright © 2010 Pearson Education, Inc.
a) longer
b) more green
c) heavier
d) shorter
e) more constant
Question 10
Wien’s law tells us that the
hotter an object, the _____
the peak wavelength of its
emitted light.
a) longer
b) more green
c) heavier
d) shorter
e) more constant
Wien’s law states that
hotter stars appear more blue in color,
and
cooler stars appear more red in color.
Copyright © 2010 Pearson Education, Inc.
Question 11
We estimate the
surface temperature
of a star by using
Copyright © 2010 Pearson Education, Inc.
a) its color.
b) the pattern of absorption lines in its
spectrum.
c) Wien’s law.
d) differences in brightness as measured
through red and blue filters.
e) All of the above are used.
Question 11
We estimate the
surface temperature
of a star by using
Copyright © 2010 Pearson Education, Inc.
a) its color.
b) the pattern of absorption lines in its
spectrum.
c) Wien’s law.
d) differences in brightness as measured
through red and blue filters.
e) All of the above are used.
Question 12
Which spectral classification
type corresponds to a star
like the Sun?
Copyright © 2010 Pearson Education, Inc.
a) O
b) A
c) F
d) G
e) M
Question 12
Which spectral classification
type corresponds to a star
like the Sun?
a) O
b) A
c) F
d) G
e) M
The OBAFGKM classification scheme is based on absorption lines.
Copyright © 2010 Pearson Education, Inc.
Question 13
The key difference
between the
spectra of B stars
and G stars is
Copyright © 2010 Pearson Education, Inc.
a) B stars show strong hydrogen lines;
G stars show weaker hydrogen lines.
b) B stars show few metal lines; G stars
show many.
c) B stars have no metal atoms.
d) G stars have no hydrogen atoms.
e) Both a and b are true.
Question 13
The key difference
between the
spectra of B stars
and G stars is
a) B stars show strong hydrogen lines;
G stars show weaker hydrogen lines.
b) B stars show few metal lines; G stars
show many.
c) B stars have no metal atoms.
d) G stars have no hydrogen atoms.
e) Both a and b are true.
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.
Copyright © 2010 Pearson Education, Inc.
Question 14
Astronomers
can estimate
the size of a
star using
Copyright © 2010 Pearson Education, Inc.
a) apparent brightness.
b) direct observation of diameter.
c) temperature.
d) distance to the star.
e) a, b, and c are all true.
Question 14
Astronomers
can estimate
the size of a
star using
a) apparent brightness.
b) direct observation of diameter.
c) temperature.
d) distance to the star.
e) a, b, and c 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.
Copyright © 2010 Pearson Education, Inc.
Question 15
Eclipsing binary
stars are very
useful for
determining the
Copyright © 2010 Pearson Education, Inc.
a) ages of stars.
b) absolute luminosities of stars.
c) masses of stars.
d) distances to stars.
e) rotation rates of stars.
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.
Copyright © 2010 Pearson Education, Inc.
Question 16
What is the single most
important characteristic
in determining the
course of a star’s
evolution?
Copyright © 2010 Pearson Education, Inc.
a) density
b) absolute brightness
c) distance
d) surface temperature
e) mass
Question 16
What is the single most
important characteristic
in determining the
course of a star’s
evolution?
a) density
b) absolute brightness
c) distance
d) surface temperature
e) 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.
Copyright © 2010 Pearson Education, Inc.