the best method of determining the distance to a relatively near galaxy is
A a bright cepheid
B novae
C bright emission nebulae
D no choice
if a spectral line is Doppler shifted in such a way that its wavelength is increased, then its frequency
A remains the same
B is decreased
C is increased
D can't tell
star a has a parallax twice that of star b. what can you say about the relative distances of the two stars?
A star a is twice as far away as star b.
B star b is twice as far away as star a.
C you cannot tell anything about their relative distances without knowing the actual parallaxes.
D you cannot tell anything about their relative distances because parallax is related to
motion and not to distance.
the determination of stellar parallax is important because it allows the direct determination of
A mass
B distance
C velocity
D all of the above
the parallax of a star is used to determine its
A size
B distance
C surface temperature
D age
variable stars, such as cepheid variables, are used in what important measurement in astronomy?
A surface temperature measurement
B rotation speeds of galaxies
C distance measurement
D the keeping of accurate time
what observed quantities must be known to find the distance to a cepheid variable
A its apparent brightness and period
B its period only
C its actual brightness and period
D its actual and apparent brightness
distances to nearer galaxies are measured using
A parallax.
B red shift.
C cepheid variables.
D pulsars.
E relativity theory.
generally speaking, the more distant a galaxy is from us, then the
A smaller and fainter it appears.
B smaller and brighter it appears.
C larger and fainter it appears.
D larger and brighter it appears.
the parallax of a star is a measure of its
A age
B distance
C size
D no choice
a useful tool in measuring distances is the relationship between the period and luminosity of
A supernovae.
B pulsars.
C novae.
D cepheid variables.
E binary stars.
suppose a star has a large parallax; that means it is
A very far from the sun.
B very close to the sun.
cepheid variables are significant because
A their actual brightness can be determined from a knowledge of the variational period
B their actual brightness can be determined from a single color measurement
C they are all the same distance away from us
D they are pulsating white dwarfs
if I want to measure the distance to a galaxy that is suspected to be seven billion light-years away, the only method astronomers presently have for m to use is
A the cepheid period-luminosity law
B using the brightest blue supergiants as standard candles
C Hubble's law
D you can't fool me; we have no way of measuring distances to galaxies that far away
stellar parallax
A is the apparent shift in star positions due to atmospheric effects.
B is the apparent shift in star positions due to the Earth's motion.
C is the cause for the sun's apparent motion among the stars.
D was not observed before the invention of the telescope.
E both (b) and (d) above.
which of the following are examples of the term standard candle?
A cepheids
B the brightest galaxy in a cluster
C supernovae
D all of the above
the distance to a nearby galaxy is most accurately determined by
A geometric means
B observing a supernova in it
C observing a cepheid variable in the galaxy
D the parallax method
which of the following is the most direct way of measuring the distance to a celestial object
A cepheid variable method
B parallax method
C Hubble law method
D Doppler shift method
the distances to nearby stars can be measured by]
A comparing the apparent magnitudes of several stars.
B bouncing radar pulses from their surfaces.
C measuring the time it takes light to get here from them.
D measuring their shifting motion against background stars through the year.
E both (b) and (c) above.
what property makes cepheid variable stars so useful
A their distance is easily determined by other means
B the amount of light they emit varies
C their light variation is regular
D their period of variation is related to their actual brightness
which of the following distance determining methods is useful only for objects within our galaxy
A standard candle
B parallax
C cepheid variable star
D none of these
when a star's heliocentric parallax is measured, a small parallax means that the star is
A relatively far away.
B relatively close by.
C not very bright.
D small in radius.
E small in mass.
the use of supernovae as standard candles for determining distance assumes that
A all supernovae have the same actual brightness
B all supernovae occur in galaxies
C all galaxies are moving away from us
D supernovae explosions occur in cepheid variable stars
a major assumption made when judging distances to galaxies by the "smallness means farness" criterion is that
A galaxies appear smaller the farther away they are.
B all galaxies of the same type are about the same size.
C smaller galaxies are fainter.
D the size of a galaxy depends on where it is in space.
the period of variability of a cepheid variable star is directly related t which stellar parameter, which then provides a reliable method for the measurement of distances to stars?
A surface magnetic field
B velocity away from Earth
C surface temperature
D luminosity
the distance to a nearby galaxy can be found by observing
A its parallax
B its color
C its brightness
D a cepheid variable star in it.
cepheid variables are important as
A distance indicators.
B speed indicators.
C mass indicators.
D size indicators.
E none of the above.
the two factors which must be observed about a cepheid, in order to make it a distance indicator are
A size and temperature
B size and period
C mass and temperature
D period and apparent brightness
the parallax shifts of stars on the other side of the milky way from us are
A the greatest of any stars in the galaxy
B greater than a minute of arc, but less than a second of arc
C greater than a second of arc, but less then a minute of arc
D impossible to measure at present
cepheids are good distance indicators because there is a relationship between their period and their
A distance
B apparent brightness
C actual brightness
D central temperature
the most accurate method of determining distances to nearby galaxies uses
A large galaxies in a cluster
B bright cepheid variable stars
C bright clouds of gas
D no choice
the method of stellar parallax is the fundamental method for determining distances to other stars, what basic fact makes these determinations possible?
A the Earth rotates once a day
B the Earth revolves around the sun once a year
C stars have proper motions
D some stars pulsate
the distances to the most remote galaxies can be determined using
A parallax
B main sequence fitting
C cepheids
D none of the above
cepheid variable stars are important to astronomers because their period of variation is related to their
A size
B composition
C rotation
D actual brightness
which of the following standard candles would be useful for finding the distances to the most distant galaxies
A supernovae
B bright star in a galaxy
C brightest star cluster in a galaxy
D brightest galaxy in a cluster
which of the following is not a standard for finding distances?
A cepheid variables
B novas in external galaxies
C megaparces
D h II regions
E red shift in spectra of galaxies
in order for a class of objects to be used as a standard candle, we must first determine
A their period
B whether they exist in all galaxies
C the distance to one of the objects
D their speed away from us
we calculate the distances to the most distant galaxies by
A the HR diagram.
B Einstein's equation.
C use of the big bang theory.
D nova, supernovae, and cepheid variables in those galaxies.
E the Hubble law.
a cepheid variable star changes its light output by
A changing its size
B changing its distance from us
C moving in orbit about an obscuring object
D processes which are not at all understood
cepheid variables are important to us in calculating
A the distances to galaxies.
B the compositions of stars.
C the compositions of the interstellar medium.
D the ages of galaxies.
E the temperatures of stars.
the distances to the most distant clusters of galaxies are determined by
A measuring the periods of cepheid variables.
B measuring the size of the brightest h II regions.
C measuring the brightness of the brightest stars.
D using the value of Hubble's constant and the measured red shift.
E using heliocentric parallax.
from only the period of a cepheid variable star, one can determine its
A distance
B actual brightness
C apparent brightness
D parallax
for the most distant clusters of galaxies, which method is used to find their distance
A large galaxies in a cluster
B bright cepheid variable stars
C bright clouds of gas
D no choice
cepheid variables can be used to find distances because their
A luminosity is related to their period.
B radial velocity is related to their mass.
C distance is related to their mass.
D magnitude is related to their color.
E period is related to their radial velocity.
supernovae can be used to find distances only if all supernovae
A are traveling at the same speed
B are in spiral galaxies
C obey Hubble's law
D reach the same actual brightness
the most important property of cepheid variable stars, compared to other types of stars, is
A that they are very large
B that they are all quite far away
C the relationship between their period and their apparent brightness
D the relationship between their period and their actual brightness
parallax would be easier to measure if
A the Earth's orbit were larger
B the stars were farther away
C the Earth moved faster along its orbit
D all of these
the difference between a galaxy's true brightness and its apparent brightness is a measure of its
A distance
B brightness
C temperature
D no choice
parallax of a nearby star is used to estimate its
A distance from Earth
B surface temperature
C apparent brightness
D physical size or diameter
in a distant group of stars there is a cepheid variable. what observation do you need to make to find the distance to the group of stars?
A apparent magnitude only
B period only
C a and b only
D a and b and chemical composition
which of the following is the most accurately known: the distance to
A nearby stars
B cepheid variable stars
C nearby galaxies
D all are equally well known
cepheid variable stars can be used to determine distances because
A they all have the same period
B they all have the same actual brightness
C there exists a relationship between period and actual brightness
D there exists a direct relationship between period of pulsation and distance
cepheid stars are
A stars at an early stage in stellar evolution, pre- main sequence
B white dwarf stars, late in their evolutionary life
C stars which pulsate in brightness, size and temperature
D members of binary systems, in which one star periodically eclipses the other
cepheid variable stars are important to astronomy primarily because they allow us to determine stellar
A distance
B mass
C temperature
D chemical composition
which of the following methods can be used for the most distant object
A cepheid variable star
B geometrical
C "standard candle" galaxy
D parallax
which of the following is not a method of determining distances to galaxies
A cepheid period-luminosity relation
B measurements of annual parallax motions of galaxies
C assuming that all supernovae reach the same absolute magnitude at maximum brightness
D assuming that the brightest galaxy in any cluster of galaxies has the same intrinsic
brightness
the larger the parallax of an object
A the closer it is
B the farther away it is
C the larger it is
D no choice
the distances to the nearest galaxies can be determined using
A parallax
B main sequence fitting
C proper motions
D cepheids
stellar parallax is used to determine which of the following properties of nearby stars?
A apparent brightness
B spectral type and surface temperature
C rotation periods
D distance from Earth
cepheid stars are useful to astronomers as indicators of
A the existence of black holes
B distance, particularly to nearby galaxies
C stars with very high speed motion
D white dwarf star behavior
an important relation observed for cepheid variables is that between
A actual brightness and temperature
B period and actual brightness
C period and radius
D mass and temperature
the time required for one complete cycle of a variable star is its
A hour
B day
C year
D period
cepheids are
A intrinsically bright variable stars
B red giant stars
C white dwarf stars
D very long period variable stars
one reason that cepheid variables are important to astronomers is that there is a relationship between the star's average luminosity and its
A color
B position in the galaxy
C type
D period of variations
cepheid variable stars are used in what important measurement in astronomy?
A the measurement of the surface temperatures of stars
B the measurement of the distances to stars
C the keeping of accurate time
D the measurement of the rotation speeds of galaxies
a cepheid variable star is characterized by
A regular pulsations
B minor surface explosions
C rotation of a "hot spot" into view
D periodic eclipses.
in order to infer the distances to other galaxies, we assume that
A all galaxies are the same.
B the universe is expanding.
C the same types of objects are the same in all galaxies.
D space is the final frontier.
the parallax method is useful for finding the distance to
A all stars in our galaxy
B only the nearest stars to the sun
C some nearby galaxies
D any visible object
the larger the parallax of a star
A the farther away it is
B the faster it is moving
C the brighter it is
D the closer it is
compared to the method discussed for finding the distance to the sun, the parallax method differs in that
A the actual brightness of the star must be known
B a much longer baseline between points of observation is used
C only certain types of stars can be used
D planets must be detectable around the star
in order to measure the distance to the sun, one must be able to measure angles and
A distances to other planets
B the distance to the moon
C distances on the Earth
D the size of the Earth's orbit
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