what is the most important general difference between the stars found in globular clusters and those in open clusters?
A globular cluster stars have a greater mass.
B globular cluster stars have a younger age.
C globular cluster stars have a lower percentage of metals.
D globular cluster stars are bluer in color and so hotter.
as a cluster of stars evolves, which stars become red giants first?
A stars with masses like the sun's.
B stars with masses smaller than the sun's.
C the most massive stars (upper main sequence).
D the least massive stars (lower main sequence).
E the stars with the most heavy elements.
globular clusters are
A newly formed clusters of stars
B clusters which have escaped from the galaxy
C remnants of the first generation of stars in our galaxy
D satellite galaxies to our own galaxy
the age of a cluster of stars can best be estimated by finding
A its temperature-luminosity diagram's turnoff point
B the abundance of helium shown in its stars' spectra
C the percentage of its stars which are white dwarfs
D the percentage of its stars which are red giants
previous generations of stars can be characterized by
A very massive stars
B enriched in the heavy elements
C very few of the heavier elements
D all such stars have vanished from view and their characteristics are not known.
how does comparing the HR diagrams of open and globular star clusters confirm astronomers' general ideas about stellar revolution?
A the diagrams for all the clusters are the same.
B the diagrams indicate that all the stars have the same age.
C the top of the main sequence turns off at different points indicating that massive stars evolve more quickly.
D the diagrams show the observed path that stars take through space.
hr diagrams of very young clusters of stars:
A have all of their stars on the main-sequence.
B have only the high mass stars on the main-sequence.
C have only their low mass stars on the main-sequence.
D have their most massive stars still on the hayashi track.
one major difference between the stars in an open (galactic) cluster and those in a globular one is that the stars in the globular are
A more massive.
B younger.
C deficient in heavy elements (metals).
D never to evolve any more.
a galactic cluster can be identified observationally by
A the common spectral type of the members
B the common actual brightness of the members
C the common proper motion of the members
D the proximity of the members in space
star clusters are very useful objects to study because
A they are very easily photographed
B the stars in a given cluster are at the same distance and of the same age
C all are of the same mass
D all clusters were formed at the same time
compared to galactic clusters, which of the following properties does not apply to globular clusters
A most stars are old
B the distance to the cluster can be determined from the apparent brightness at the main sequence
C they are found outside the disk of our galaxy
D they contain at least a hundred thousand stars
the age of a cluster can be determined by analyzing
A the motion of the stars
B the number of stars in the cluster
C the H-R diagram of the cluster
D cepheid variables in the cluster
clusters help us to learn about the evolution of stars because stars in a cluster
A are all about the same temperature.
B are all about the same mass.
C interact with one another and affect each other's evolution.
D are all about the same age.
E can be observed more easily than individual stars.
H-R diagrams of young star clusters show
A less than about 10 stars.
B very few of the most luminous stars.
C that massive stars have not reached the main sequence.
D that low mass stars have not yet reached the main sequence.
the point where stars have left the main sequence tells us the age of a cluster because
A there is a gap between the main sequence and red giants
B more massive stars move off the main sequence faster than less massive stars
C all stars in a cluster have the same mass
D low-mass stars take longer to reach the main sequence
on an H-R diagram of a cluster of stars,
A older stars will be less evolved than younger stars.
B stars off the main sequence will be more massive stars.
C all stars will be found on the main sequence.
D the main sequence will be shifted up or down depending on the mass of the cluster.
star clusters are very useful objects to study because
A all are at the same distance
B all were formed at the same time
C the stars in a given cluster are at the same distance
D they are very easily photographed
which of the following can be learned about the stars in a cluster from a study of their H-R diagram
A age of the cluster
B distance to the cluster
C mass of at least some of the stars in the cluster
D all of the above
the main general features which make clusters of stars useful to astronomers are that
A stars are all at same distance from Earth, have same surface temperature, and joined the cluster at various times
B stars all have the same intrinsic brightness, but differ only in size and surface temperature
C stars all have the same apparent magnitudes, the same surface temperatures and the same sizes
D the stars are at the same distance from Earth and were formed at approximately the same
time
how does comparing the H-R diagrams of galactic and globular clusters confirm astronomers' general ideas about stella revolution?
A the diagrams for different clusters are all the same.
B the diagrams indicate that all stars have the same age.
C the diagrams show that the top end of the main sequence turns off at different points, indicating that more massive stars evolve faster.
D the diagrams show the observed path that stars take through space.
we learn the age of a star cluster by
A studying the Doppler shift of radio waves from it.
B studying the reflection of light from stars in the cluster.
C plotting the stars of the cluster on an H-R diagram.
D observing supernovae within the cluster.
E determining the number of stars within the cluster.
a young star cluster will have
A a redder turn-off point.
B a bluer turn-off point.
C fewer stars.
D fewer luminous stars.
the H-R diagram for cluster a consists of stars on the main sequence, while the diagram for cluster b has stars both on the main sequence and just ab the main sequence at lower temperatures. which cluster is older?
A cluster a
B cluster b
C both clusters are the same age
D more information is required
an association is
A an old open cluster
B an expanding group of young o and b stars
C the remnant of a stellar explosion
D no choice
star clusters can be used to test the theory of stellar evolution because all stars in the cluster
A are the same size
B formed from the same cloud of gas
C are moving randomly
D are the same age
H-R diagrams of clusters are important, since all stars in a cluster have approximately the same
A actual brightness
B age
C temperature
D Doppler shift
on an HR diagram of a cluster of stars,
A older stars will be more highly evolved than younger stars.
B stars off the main sequence are more massive.
C all stars are always on the main sequence.
D o stars are at the bottom of the main sequence.
which of the following is not true of globular clusters?
A they contain young stars
B they have a symmetrical shape
C they orbit around the galaxy
D they contain very little gas and dust
which of the following are concentrated in the galactic disk
A globular clusters
B open clusters
C extra-galactic "nebulae"
D no choice
the study of stars in clusters has helped astronomers to understand
A the action of nuclear fusion in stars
B the reason for differences in surface temperatures of stars
C the mechanism of mass loss in stars
D stellar evolution, the development of stars with time
the age of a cluster of stars can be judged by
A the turnoff point on the main sequence of its hertzsprung-russell diagram
B the number of novae per year occurring within the cluster
C the total number of stars within the cluster
D the amount of radioactive elements detected on star surfaces
the HR diagram of an old cluster
A will have a turn off point at the lower end of the main sequence
B will have a turn off point at the upper end of the main sequence
C will show all of the stars on the main sequence
D none of the above
the age of a cluster can be determined by
A a number count of the stars in the cluster
B the turnoff point on the main sequence of its HR diagram
C measuring its speed relative to the sun
D its position in the sky with respect to the sun
which of the following is not true of globular clusters
A they contain about 100,000 stars
B when photographed they appear circular with so many stars at the center that they can't be resolved
C they are young
D they form a halo around the galaxy
which of the following kinds of stars in the milky way has the most "heavy elements" (elements heavier than helium)?
A the first stars to form, which used up most of the available heavy element
B the stars in globular star clusters
C the stars farthest from the disk of the milky way
D the stars that formed at least a couple of billion years after the milky w began to form
which one of the following features does not exist in the H-R diagram of a typical old cluster?
A red giant branch
B lower main sequence of cool stars
C upper main sequence of hot stars
D horizontal branch
the two types of star clusters in the milky way are called
A elliptical and globular clusters
B irregular and spiral clusters
C open and globular clusters
D galactic and extragalactic clusters
which statement about globular clusters is true
A they were all formed in the center of our galaxy
B they contain stars with high metal abundance
C they are associated with gas and dust
D they are found in the galactic halo
which of the following is not an assumption made in the study of star clusters
A all the stars are at the same distance
B all the stars formed at the same time
C all the stars have the same chemical composition
D all the stars have the same mass
which of the following provides the most direct test of the theory of stellar evolution
A detailed observations of the sun
B the interpretation of the H-R diagram of stars very near to us
C the interpretation of the H-R diagram of a cluster of stars
D the existence of white dwarf stars
compared to galactic clusters, globular clusters
A are older
B have fewer stars
C are outside the galaxy
D have no remnants of gas and dust between the stars
in a middle aged cluster, the red giants are probably
A pre-main sequence stars
B foreground stars not in the cluster
C medium mass post-main sequence stars
D background stars not in the cluster.
open clusters of stars
A contain a higher percentage of heavy elements than do globular clusters
B make up most of the mass of a spiral galaxy's disk
C make up most of the mass of a spiral galaxy's halo
D remain together longer than any other type of cluster
stars in a cluster can serve as a test for theories of stellar evolution because
A all are at the same distance
B all are the same size
C all are the same mass
D all are the same age
"about 100,000 stars packed into a ball of diameter 100 ly" describes
A an open cluster
B a galaxy
C another solar system
D a globular cluster
H-R diagrams of clusters are important, since all stars in a cluster have approximately the same
A actual brightness and color
B distance and age
C temperature and mass
D spectral type and color
from a study of a cluster H-R diagram, one can determine
A the size of the individual stars directly
B the approximate age of the cluster
C the number of white dwarfs which have faded from view
D all of the above.
the milky way's globular clusters
A have fewer stars than do open clusters
B are older than most open clusters
C are more numerous closer to the center of the galaxy than in its outer reg
D are found in the large Magellanic cloud
the main sequence turn-off point is useful in determining a cluster's
A mass
B age
C distance
D velocity
star clusters are useful in the study of stellar evolution because
A all the stars in the cluster are at the same distance and were formed at about the same time
B comparing the H-R diagram of one cluster with another allows you to determine the age of each cluster
C all the stars in the cluster have the same mass and are at the same distance from you
D the stars in a cluster all evolve at the same rate
a globular cluster is a group of stars
A with many thousand members, of different ages but with the same chemical composition
B with a few hundred members, still embedded in the gas from which they were formed
C with many thousand members, mostly binary, of different ages
D with many thousand members, found on the fringes of a galaxy
star cluster a has no main sequence stars hotter than 6,000 k, while the hottest main sequence star in cluster b has a surface temperature of 10,000 k
A star cluster a is older than cluster b
B star cluster b is older than cluster a
C these descriptions are so unrealistic as to make the question meaningless
D you can't tell which cluster is oldest from this information
a very old cluster
A will consist largely of main sequence stars
B will contain some main sequence stars, but only hot ones
C will contain very few red giant stars
D will contain some main sequence stars, but only cool ones
it is reasonable to suppose that all stars in a particular globular cluster have the same
A mass
B size
C luminosity
D age
where would you look for a globular cluster?
A in the galactic plane, moving in a circular orbit around the galactic center
B in the asteroid belt
C in the galactic halo, orbiting the galactic center in a long elliptical orbit
D only in elliptical galaxies
an open cluster
A is a group of 50 to a few thousand stars which formed from the same gas cl at about the same time
B a group of galaxies, such as that inhabited by the milky way and Andromeda galaxies
C is a group of stars located between galaxies
D none of the above
how does comparing the hertzprung-russell diagrams of star clusters confirm astronomers' general ideas about stellar evolution?
A the diagrams for different clusters are all the same
B the diagrams indicate that all stars have the same age
C the diagrams show that the top end of the main sequence turns off at different points, indicating that more massive stars evolve faster
D the diagrams show the observed path that stars take through space
a massive, spherical cluster of old stars is
A an open cluster
B a globular cluster
C an association
D a union
compared to an old cluster, a young star cluster will have
A a redder main sequence turn-off point
B a bluer main sequence turn-off point
C more stars
D fewer luminous stars
stars within a star cluster differ from one another in
A distance
B age
C chemical composition
D mass
an astronomer is observing a cluster of stars in our milky way galaxy. which of the following would be a way to get the age of the cluster?
A measure the Doppler shift of many stars in the cluster
B measure the luminosity and surface temperature of many stars in the cluster and make an H-R diagram
C wait until a supernova explodes in the cluster and carefully measure the rate at which it brightens
D you can't fool me: we can only find the ages of individual stars; there is no way at present
to find the ages of clusters
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