the vertical axis of an H-R diagram of the brightest stars would have to be
A the color of the star
B the actual visual brightness of the star
C the apparent brightness of the star including all wavelengths
D the speed of the star
the region of the H-R diagram occupied by most stars is the
A main sequence region
B red giant region
C white dwarf region
D quasar region
what property of a star uniquely determines where it will be on the main sequence
A temperature
B brightness
C mass
D age
stars on the main sequence
A convert helium to hydrogen in their centers
B convert helium to carbon in their centers
C convert hydrogen to helium in their centers
D have no nuclear energy sources in their centers
if the temperature of a star increased without a change in the star's size, its point on the H-R diagram would move
A up and to the left.
B up and to the right.
C down and to the left.
D down and to the right.
to construct an H-R diagram, astronomers plot random stars by their
A apparent brightness and distance
B distance and spectral type
C actual brightness and spectral type
D size and temperature
the apparent brightness of any star is, by itself, a good indicator of
A its actual brightness
B its distance
C its temperature
D nothing.
the vertical axis of an H-R diagram of the nearby stars would have to be
A the color
B the apparent brightness of the star
C the distance
D the actual brightness of the star
if you increase the temperature of a star and leave its size constant, its point on the H-R diagram will move
A up and to the left
B up and to the right
C down and to the left
D down and to the right
when plotting random stars in an H-R diagram, what must be known for each star
A color and apparent brightness
B color, apparent brightness and distance
C apparent brightness and age
D color and distance
the H-R diagram is a graph of
A apparent brightness verses actual brightness
B actual brightness verses period
C color verses age
D actual brightness verses color
star c appears blue and star d appears red. what do we know for sure?
A star c is less luminous than star d.
B star c is hotter than star d.
C star c is cooler than star d.
D star c is more luminous than star d.
we know that giant stars are larger in diameter than the sun because
A they are more luminous but have the same temperature.
B they are less luminous but have the same temperature.
C they are hotter but have the same luminosity.
D they are cooler but have the same luminosity.
the single quantity which determines where a star will be on the main sequence is its
A age
B mass
C size
D distance.
H-R diagrams of stars in a cluster can be easily obtained because all are
A the same age
B the same mass
C the same size
D the same distance
the physical property which determines where a star will be on the main sequence is
A its mass
B its age
C the relative abundance of hydrogen in the star
D which element is being consumed by nuclear reactions at the center of the star
when plotting an H-R diagram of stars in a cluster, apparent brightness can be used because
A their size and mass is constant
B they can all be observed in one photograph
C the distance of all the stars is the same
D the age of all the stars is the same
two stars of the same spectral class are plotted on a hertzsprung-russell diagram. star a is more luminous than star b. this tells you that
A star a is hotter than star b.
B star a is farther away than star b.
C star a appears brighter in the sky than star b.
D star a is larger than star b.
E none of the above.
the quantity which determines where a star will be (or was) on the main sequence is
A age
B composition
C distance
D mass
a plot of apparent brightness verses color for a cluster of stars would result in
A a totally nonsensical H-R diagram
B an inverted H-R diagram
C a shifted H-R diagram
D a plot that is impossible to make
which of the following does not have a fundamental influence on the properties of a star?
A mass
B luminosity
C chemical composition
D age
the HR diagram is a graph of the ______ and ______ of a large number of stars.
A hertzprungs, russels
B luminosities, temperatures.
C sizes, masses
D velocities, shapes
the actual brightness of a star must ordinarily be used to plot an H-R diagram to account for the effects of a star's
A temperature
B age
C distance
D velocity
in the H-R diagram, 90 percent of all stars fall
A in the giant region.
B in the supergiant region.
C among the b stars.
D on the main sequence.
the coolest normal stars have a surface temperature of about
A 200 deg f
B 5000 deg f
C 50000 deg f
D 1,000,000 deg f
stars on the main sequence
A have approximately the same age, to within a few million years
B have extremely low abundances of elements heavier than helium
C generate energy by hydrogen fusion in their centers
D are changing slowly in size, by gravitational contraction
the basic properties of stars which are used in an H-R diagram are
A mass and temperature
B color and brightness
C brightness and mass
D color and temperature
the H-R diagram is a plot of
A luminosity versus radius
B mass versus temperature
C luminosity versus temperature
D mass versus luminosity
which of the following is the same for all stars along a horizontal line on an HR diagram?
A temperature.
B diameter.
C mass.
D luminosity.
stars on the main sequence
A are changing slowly in size, by gravitational contraction
B are at an intermediate stage of evolution between red giant and white dwarf
C have approximately the same age, to within a few million years
D generate energy by hydrogen fusion in their centers
compared to the sun, stars near the top of the H-R diagram are
A about the same brightness
B about a hundred thousand times brighter
C much redder
D much hotter
the H-R diagram is
A a plot of stellar temperature versus apparent brightness for a random sample of stars
B a plot of stellar mass versus luminosity
C a plot of temperature versus actual brightness for a sample of stars
D a plot of apparent brightness versus luminosity
star x has the same surface temperature but twice the actual brightness of star y. we may conclude that star x is
A redder than star y
B smaller than star y
C larger than star y
D bluer than star y
the hertzsprung-russell diagram is a plot of the following two stellar parameters:
A brightness and mass
B mass and surface temperature
C radius and mass
D brightness and surface temperature
on the H-R diagram, a vertical change upward corresponds to a
A dimming
B brightening
C heating
D cooling
in terms of actual brightness and temperature the main sequence goes from
A high actual brightness, low temperature to low actual brightness, high temperature
B high actual brightness, high temperature to high actual brightness, low temperature
C low actual brightness, low temperature to high actual brightness, high temperature
D low actual brightness, low temperature to high actual brightness, low temperature
a star's color gives an indication of its
A actual brightness
B age
C temperature
D no choice
if we plot ten stars in an H-R diagram, all with the same true brightness but different temperatures, they
B would be all over the diagram
A would all lie on the main sequence
C would form a horizontal line
D would form a vertical line
stars on the main sequence
A all have the same mass
B are placed with higher mass at higher temperature
C are placed with higher mass at lower temperature
D are placed randomly with respect to mass
at the lower right corner of an HR diagram you find
A stars like the sun
B hot stars
C giant red stars
D small red stars
astronomers have discovered a star that evolves in a strange fashion: its brightness decreases while its temperature increases. in what direction does this star "move" in the H-R diagram?
A upper right to lower left
B upper left to lower right
C straight up and down
D left to right
the relationship between mass and luminosity of stars on the main sequence is that
A the luminosity is independent of the stellar mass
B the greater the stellar mass, the less the luminosity
C the luminosity of stars rises to a peak at around a mass of 1 solar mass, and decreases as mass increases beyond this limit
D the greater the stellar mass, the larger the luminosity
a star directly below the sun on the HR diagram would be _____ than the sun
A larger
B smaller
C cooler
D hotter
an H-R diagram is a plot of two characteristics of stars. one of these is
A mass
B diameter
C surface temperature
D age
the main sequence extends from
A high luminosity, high temperature to low luminosity, low temperature
B high luminosity, low temperature to low luminosity, low temperature
C high luminosity, low temperature to low luminosity, high temperature
D high luminosity, high temperature to low luminosity, high temperature
two stars of the same surface temperature are plotted on an HR diagram. star a is more luminous than star b. this tells you that
A star a is hotter than b.
B star a is further away than b.
C star a is larger than star b.
D none of the above.
when plotting an H-R diagram of a cluster, apparent brightness can be used because all the stars have the same
A distance
B age
C color
D mass
Return to Table of Contents