Astronomy 122

Flashcard maker : Brooke Sharp
When visible light passes through a prism of glass, which
wavelengths of light are refracted most by the glass?
the shorter wavelengths (blue)
The best shape for the cross-section of a large astronomical mirror in order to produce the sharpest images of very distant objects is
a parabolic shape
Where are new stars born?
within dark clouds in interstellar space
Which of the following types of telescope will suffer from chromatic aberration unless expensive measures are taken to avoid it?
refracting telescope
Chromatic aberration occurs in a telescope when
the different colors of light come to different focal points
Astronomy from space vehicles is particularly useful because
the telescope is above the Earth’s absorbing and distorting atmosphere and can measure radiation over a very wide wavelength range.
On the absolute scale of temperature (in degrees Kelvin, or Kelvins), the zero of the scale corresponds to
the temperature at which the motion of atoms and molecules ceases.
On the absolute Kelvin temperature scale, the temperature of freezing water is about
+273 degrees
As a new star evolves from cool dust and gas to a hot star, the peak wavelength of its spectrum of electromagnetic radiation will change from what wl to what wl
change from the infrared to the visible wavelengths
Which of the following are made of “star dust”?
a. spiders
b. buildings
c. the Sun
d. all of the above.
a. spiders
b. buildings
c. the Sun
—-> d. all of the above.
Increasing the diameter of the mirror or lens of a telescope will:
improve its resolution
Refracting telescopes are limited because:
lenses bend different colors of light different amounts
Comparing refracting and reflecting telescopes:
it is practical to build larger reflecting telescopes
Which of the following types of the electromagnetic radiation could provide the best resolution in the same size instrument?
visible light
The Doppler Effect is used by astronomers to determine:
radial speeds of stars
A star whose surface temperature is 100,000 K will emit a spectrum whose peak wavelength is
at ultraviolet wavelengths
We use radio astronomy because…
radio waves pass right through dust
The early workers in spectroscopy (including Kirchhoff with laboratory spectra) discovered which very significant fact about the spectra produced by hot gases, such as elements heated in a flame.
each chemical element produces its own characteristic pattern of spectral lines.
Atoms in a hot gas emit a spectrum, which is
a series of specific colors (“lines”), unique to the type of atom, but fixed in color when gas temperature changes
The specific colors of light (“lines”) emitted by an atom in a hot thin gas (e.g. in a tube in a laboratory or a gas cloud in space) are caused by
electrons jumping to lower energy levels, losing energy as they do so
If light from a hot, dense star passes through a cool cloud of gas
only specific wavelengths of light (“absorption lines”) will be removed from the spectrum
An atom is now known to consist of
a small, massive, electrically charged core (“nucleus”) with electrons surrounding it
A spectrum consisting of many dark lines superimposed on a continuous spectrum is
an absorption-line spectrum
Ionization of an atom occurs when
an electron is removed from the atom
Suppose the spectrum of a solar-type star shows an equivalent set of dark absorption lines, but with one exception. Every line appears at a slightly longer wavelength, shifted towards the red end of the spectrum. What conclusion can be drawn from this observation? (Hint: recall the Doppler effect)
the star is moving rapidly away from the Earth
Stars that are just being formed are best observed by
radio waves
When light from the concave primary mirror of a telescope is reflected by a small secondary mirror through a hole in the primary to its focus, this is called the
Cassegrain focus
Who was the first astronomer to build and use a telescope to observe the night sky?
The reflecting astronomical telescope with an eyepiece at the side is named for?
The Helium atom is composed of
two electrons and a nucleus of two protons and two neutrons
Hans Bethe and other physicists explained the source of the Sun’s energy as
the fusion of atomic nuclei
Choose the correct order of electromagnetic radiations, from shortest to longest wavelength: Visible, Radio, Uv, IR
UV, visible, IR, radio
What is the one fundamental difference between x-rays and radio waves?
their wavelengths are very different
Refraction is
the bending of light as it crosses the boundary from one transparent material to another (such as a lens)
What happens when a beam of white light (containing all colors) is passed through a prism of glass?
different colors are refracted at different angles to produce a spectrum
The light-gathering power of a telescope is related directly to
the area of its primary mirror or lens
Compared with the 100-inch diameter Mount Wilson telescope, the 200-inch diameter Mount Palomar telescope has a greater light-gathering power, by a factor of
The major cause of blurring and unsharp images of objects observed through very large telescopes, at the extreme limit of magnification, is
air turbulence in the Earth’s atmosphere
What is the main reason for combining many radio telescopes together into an interferometer with large distances between telescopes?
to obtain much sharper images of sources
The main reason for carrying a telescope and scientific equipment in an aircraft in order to carry out infrared astronomy is
to avoid the absorbing effects of water vapor upon IR radiation
Given that a 6000 K surface emits radiation (“blackbody theory”) with a peak wavelength of 0.48 microns a 12000 K surface will have a peak _____
0.24 microns
Suppose star A has a surface temperature of 6000 K and star B has a surface temperature of 12000 K. Compare the energy emitted per surface area of each star.
star B will emit sixteen times star A
Parallax can be used to determine star distances for:
stars relatively close to the sun
In understanding stars, the Bohr atom is useful for the following purpose(s):
it helps us understand the spectral lines
Radio waves travel through space at what speed?
at the speed of light, 300,000 km/sec
The Doppler Effect is the change in the wavelength of light caused by the source in respect to what?
moving with respect to the observer
The peak wavelength in the spectrum of light from a star can be used to determine its
surface temperature
What special event was observed in the Large Magellanic Cloud in 1987?
first supernova visible on Earth to the naked eye in 400 years
The two windows of the atmosphere are
the optical window and the radio window
What type of radiation has wavelengths greater than 100 microns?
radio waves
What type of radiation has wavelengths in the range of 0.7 microns to 100 microns
it is infrared radiation
The typical wavelength of visible light is
0.5 microns
What is the name of the large telescope launched from the Space Shuttle in 1990?
The Hubble Space Telescope
How many light years in one parsec?
about 3.3
Star A appears to have the same brightness through a red and blue filter. Star B appears brighter in the red than in the blue. Star C appears brighter in the blue than in the red. Rank these stars in order of increasing surface temperature.
B, A, C
Electronic detectors often used to record telescopic images are
What new development in telescopes are bringing striking improvements in ground-based optical telescopes?
active and adaptive optics
Light with a wavelength of 400 nm (or 0.4 microns) is perceived to be
How many more years will the Sun shine (approximately)?
5 billion years
Which photon has the highest energy?
An advantage of a visible light telescope is
the Earth’s atmosphere is transparent to visible light
The best wavelength for penetrating dusty regions of interstellar space, and detecting otherwise hidden objects is
radio waves
The Big Bang mostly created which elements?
hydrogen and helium
The Earth’s atmosphere is opaque to
a. gamma-rays
b. X-rays
c. ultraviolet radiation
d. all of the above
a. gamma-rays
b. X-rays
c. ultraviolet radiation
—-> d. all of the above
The Earth’s turbulent atmosphere will smear point like images of stars into “seeing disks that are how big in diameter
a few arc seconds in diameter
What is the approximate frequency of visible light?
6 x 1014 Hz
What is the approximate energy carried by a photon of visible light
4 x 10-19 Joules
Emission lines from molecules result from
a. electron orbital changes
b. changes in the vibrational state of the molecule
c. changes in the rotational state of the molecule
d. all of the above
a. electron orbital changes
b. changes in the vibrational state of the molecule
c. changes in the rotational state of the molecule
—-> d. all of the above
A photon of light is emitted from an atom when what happens to the atom
when an electron drops from an energy state to a lower energy state
The relationship between energy (E) and the frequency of a photon (f) is
E = hf
A photon of wavelength 10 micro-meters is considered what type of wavelength
infrared radiation
A spectroscope (or spectrograph) is
an optical device that records a spectrum
Different elements can be distinguished by their emission spectrum because why
they each produce different specific emission line wavelengths
The width of an emission line can be broadened through
a. thermal broadening
b. rotational broadening
c. collisional broadening
d. all of the above
a. thermal broadening
b. rotational broadening
c. collisional broadening
—> d. all of the above
The temperature of a star can be inferred from
a. the peak of the continuous spectrum of the star
b. the width of the absorption lines in the star’s spectrum
c. the specific lines that are present in the star’s absorption spectrum
d. all of the above
a. the peak of the continuous spectrum of the star
b. the width of the absorption lines in the star’s spectrum
c. the specific lines that are present in the star’s absorption spectrum
—> d. all of the above
Astronomers analyze starlight to determine a star’s
a. temperature
b. composition
c. motion
d. all of the above
a. temperature
b. composition
c. motion
—-> d. all of the above
Compared with slowly rotating stars, the fastest spinning stars have absorption lines that are
broad and fuzzy
Compared with a complex atom like neon, a simple atom such as hydrogen has more or fewer excited states?
fewer excited states
Light behaves as a wave or particle?
sometimes as a wave, and sometimes as a particle
The Big Bang occurred how many years ago?
about 14 billion years ago
The distance to the closest star beyond the Sun is about
4 light-years
How is a parsec defined?
the distance which has a 1 arcsecond parallax
What process has created most of the heavier elements (beyond hydrogen and helium) in the Universe?
nuclear fusion within stars
The resolution of a typical radio astronomy telescope for 1 meter wavelength is about
10,000 arc-seconds
What type of electromagnetic radiation is made of photons with the lowest energy?
Radio waves
What color of visible light has the shortest wavelength?
What molecule in the atmosphere is a strong absorber of infrared radiation?
Water (or H20)
The diameter of the primary mirror of the Hubble Space Telescope is 2.4 meters.
Calculate the angular resolution for visible light.
(Hint: ang. res. (in arc-secs) = 0.25 x wavelength(microns) / diameter(meters) )
ang. res = 0.25 x 0.5 / 2.4 arc-sec = 0.05 arc-sec
What was the first astronomical radio source discovered by Karl Jansky?
The Center of the Milky Way Galaxy
Calculate the distance of one light year in kilometers, beginning from the speed of
light (show the calculation).
One light-year = the speed of light multiplied by the length of a year

= 300,000 km/sec x 60 sec/min x 60 min/hour x 24 hours/day x 365 days

= 9.5 x 1012 kilometers

What effect causes the colors of a moving object to be shifted to red or blue .
Doppler Effect
What is the brightest star in the evening sky?
The most common element of main-sequence stars is
The radius of the Sun is about
700,000 kilometers
What is the approximate density of dust in the interstellar medium?
1000 dust particles /km3
The interstellar gas (by number of atoms) is
90% hydrogen, 9% helium, traces of other atoms
HII regions are characterized by
ionized hydrogen
A solar flare is
an explosion on the solar surface
How many times bigger is a red giants radius than the suns?
a red giant’s radius may be tens to hundreds of times the radius of the Sun
What is equivalent to brightness?
apparent magnitude
Energy is transferred from the solar core to the bottom of the convection zone by
Solar granulation is an indication that
energy is transported out of the Sun by convection
Approximately what fraction of stars within our local neighborhood are main sequence stars?
90 %
What is the approximate density of atoms in the interstellar medium?
1 atom/cm3
The radial motion of a star is determined by
the Doppler shift of its absorption lines
Which of the following four spectral classifications represents the hottest stellar surface
temperature of these four?
a. A
b. B
c. G
d. K
a. A
–> b. B
c. G
d. K
Which of the following four spectral classifications represents the coolest stellar surface
temperature of these four?
a. B
b. K
c. A
d. G
a. B
–> b. K
c. A
d. G
The visible corona of the Sun is most effectively photographed during which eclipse?
during solar eclipses
What is the equivalent to luminosity?
absolute magnitude
What is the luminosity class of the Sun?
Stars on the main sequence generate energy how?
generate energy by thermonuclear fusion in their cores
What is the approximate expected main sequence lifetime of a star with a mass of 15 solar masses?
about 15 million years
The more massive the star the faster or slower the evolution?
the more massive the original star, the faster the evolution
Which of the following is NOT the effect of interstellar dust on starlight?
a. mutation
b. extinction
c. reddening
d. polarization
–> a. mutation
b. extinction
c. reddening
d. polarization
The age of the Sun is about
5,000,000,000 years
The luminosity of a star is a unique measure of its
total energy output
In the spectral sequence of star types, in which each spectral class has been divided into 10 intervals, the Sun is classified as
G 2
what is the order of star spectral classes from hottest to coolest
We understand that stars above the main sequence of the H-R diagram are the stars that have _____
stars with larger surface areas
The brightest star in the night sky is:
What proportion of visible stars in the nighttime sky are multiple-star systems, such as double stars?
most stars
The relationship between mass and luminosity of stars on the Main Sequence is that…
the greater the stellar mass, the larger the luminosity
The Sun’s source of energy at the present time is
thermonuclear fusion (combination) of hydrogen atoms
The evolution of a star depends predominantly upon
its initial mass
The surface temperature of a B type star is about
20,000 K
Giant magnetic bubbles of ionized gas that separate from the Suns atmosphere and escape
into interplanetary space are called
coronal mass ejections
The surface temperature of a red star is about
3000 K
A reflection nebula is what color?
is bluish in color
Compared to an excellent, research quality vacuum on Earth, the density of gas in the interstellar medium is
the interstellar medium is much less dense.
The chemical composition of the surface layers of the Sun is determined primarily by what technique?
One particular feature of the solar corona is it is high or low temp?
its very high temperature
The brightest stars in the sky were labeled by the Greeks as
magnitude 1 stars
Star A is magnitude 3 and Star B is magnitude 8 how many times brighter is star A than star B
Star A is 100 times brighter than Star B
The temperature of the core of the Sun, where thermonuclear processes can take place, is approximately
1.5 x 107 K
The average time taken for energy generated by thermonuclear fusion in the center of the Sun to
reach the surface layers and escape is calculated to be
tens or hundreds of thousands of years
The Sun has been stable for a very long time, in hydrostatic equilibrium. Which two parameters must
be in balance within the Sun?
the force of gravity and outward gas pressure
The Horsehead Nebula is what kind of nebula
an absorption nebula
What processes of heat energy transfer are important within the Sun?
radiation and convection
The total time that the Sun will spend as a main sequence star is
about 10 billion years (1010 years)
The most common molecule in a molecular cloud is
molecular hydrogen, H2
On the Hertzsprung-Russell diagram which type of star has the following characteristics:
A star with surface temperature 10,000 K, and luminosity 1/100 times that of the Sun.
white dwarf
Which main-sequence stars of the spectral classes have the greatest mass?
Which of the following regions would be hottest?
a. Death Valley
b. HI regions
c. HII regions
d. molecular clouds
a. Death Valley
b. HI regions
–> c. HII regions
d. molecular clouds
An eclipsing binary system is what?
two stars which periodically eclipse each other, as seen from Earth
Binary stars, mutually bound to each other by gravitational forces, allow us to derive which
important stellar parameter of the stars?
stellar mass
To determine the Sun’s luminosity, we must know
the distance from the earth to the Sun
Spectroscopic parallax is used to
determine the distance to main-sequence stars
Which of the following main sequence stars would have the coolest surface?
a. Spectral Class A
b. Spectral Class M
c. Spectral Class O
d. Spectral Class T
a. Spectral Class A
–> b. Spectral Class M
c. Spectral Class O
d. Spectral Class T
What is HII?
ionized hydrogen
What nebula is an absorption nebula?
The Horsehead Nebula
The distance from the Earth to the Sun is
150,000,000 kilometers
A coronal hole is
a hole in the Sun’s corona
A good example of a reflection nebula is
The Pleiades
The 21-cm line comes from
spin-flip of the electron in hydrogen
How does the temperature of a Sunspot compare to the temperature of the
solar surface?
colder in both hemispheres
The solar constant is
1400 Watts/m2
Differential rotation of the Sun refers to
the rapid speed of the rotation of the equator of the Sun
Which of the following spectral classes of stars has the longest main-sequence lifetime?
a. A
b. B
c. F
d. G
a. A
b. B
c. F
–> d. G
Which of the following spectral classes of stars has the longest main-sequence lifetime?
a. K
b. M
c. O
d. Q
a. K
–> b. M
c. O
d. Q
The radius of a main sequence star can be determined from
Luminosity and surface temperature
A star’s luminosity class is determined from
the width of its absorption lines
A good example of an absorption (or dark) nebula is
The Horsehead Nebula
The distinctive color of a reflection nebula is
blue, caused by the scattering of light from dust grains
What is the approximate ratio of hydrogen to helium in the interstellar medium,
by number of atoms?
10 to 1
The rotation period of the Solar equator is
25 days
list the following from smallest radius to largest: red giant, white dwarf, sun
white dwarf, Sun, red giant
The oldest star clusters are
globular clusters
The interstellar medium is mostly composed of
diffuse gas composed of hydrogen and helium
The surface temperature of a red giant is likely to be about
4,500 K
The surface temperature of a white dwarf is likely to be about
10,000 K
When a neutrino from the Sun reaches the Earth, what is the most likely outcome?
it passes right through the Earth, unchanged
Which of the following are NOT main-sequence stars
a. white dwarfs
b. red giants
c. red supergiants
d. all of the above
a. white dwarfs
b. red giants
c. red supergiants
—> d. all of the above
For what purpose did Charles Messier construct his catalog of objects?
To assist his search for comets
A good example of an emission nebula is
The Orion Nebula
Which of the following regions would be coldest?

a. HI regions
b. HII regions
c. molecular clouds
d. my dorm room

a. HI regions
b. HII regions
–> c. molecular clouds
d. my dorm room
The effective reaction for the proton-proton chain is
4(H) –> He + neutrinos + energy
Write an equation relating luminosity, radius, and surface temperature of a star.
Luminosity ∼ Radius2 x Temperature4
What is the second most abundant element in the Sun?
Name a star in the constellation Orion that is large enough to be having its
size resolved directly.
How often does the number of Sunspots on the solar surface reach a maximum?
Every 11 years
What is the preferential dimming of short-wavelengths by dust in the
interstellar medium called?
What is the energy transfer process that operates in the Sun via mass motion?
What is the Luminosity Class of the main-sequence stars?
The Nebula around the Pleiades is an example of what type of nebula?
Reflection Nebula
Why does the H-R diagram of a globular cluster NOT contain any stars with high
luminosity and high temperature on the main sequence?
these high-mass stars have evolved away from the main sequence
What is a stellar association?
loosely bound group of newborn stars
Approximately what temperature is required in a collapsing protostar to
ignite nuclear burning?
10,000,000 K
What do many astronomers regard as a triggering mechanism for star formation?
passage of a shock wave
What is unusual about the Algol binary?
The most massive of the two stars is still on the main sequence
The Sun will never be what kind of star
a neutron star
Most of the supernovae seen by astronomers are
in other galaxies
Newborn star clusters are often found with
emission nebulae
Which development within the deep interior of the Sun will eventually
lead to major changes?
the build-up of helium in the core
How does a medium mass star evolve, on the H-R diagram, at the end of
its main sequence lifetime?
to higher luminosity and lower surface temperature
Infrared stars within the Orion Nebula are examples of which stage of
stellar evolution?
protostar and young star
The most likely site for the manufacture of heavy elements (beyond hydrogen
and helium) in the Universe is
in the deep interiors of stars
old stars will have more or less heavy elements
stars with less abundance of heavy elements
A pulsar is composed mostly of
Which of the following processes requires the highest temperature to proceed?
Carbon fusion
A star that emits a planetary nebula is likely to become what type of star
become a white dwarf
The speed of a neutrino is close to
The speed of light
How old would a red giant star
in the sky today be?
10,000,000,000 years
The path drawn on the H-R diagram below represents the change in
a Sun-like star during the birth of the star
Where is one most likely to find a white dwarf star?
Within a globular cluster
The pre main-sequence path on the H-R diagram of a protostar depends on
its mass
During the formation of stars, the collapse of globules heats the
interstellar gas to how many kelvins?
from less than a hundred degrees Kelvin to millions
The heaviest stars are formed by collapsing clouds faster or slower than the lightest stars?
faster than the lightest stars
Stars of about twice the mass of the Sun are formed from the collapse
of interstellar clouds in how many years
about 10,000,000 years
OB associations are marked by
new star formation
What type of star is the smallest?
neutron star
ZAMS stands for
zero-age main sequence
A brown dwarf is
a failed star
When is hydrostatic equilibrium established in a solar mass star?
when the core of the star reaches 10,000,000 K
A chain-reaction of star formation can be propagated by
supernovae explosions
The energy for the initial increase in the temperature of a collapsing cloud
in star formation comes from
gravitational energy
The heavy elements you are made of were formed in
a supernova explosion
True or false, supernovae occur only in binary star systems.
The expected aging of two stars in a binary system would normally be: a- the smaller star evolves quicker b- the bigger star evolves quicker?
b-the most massive star would evolve quickest
Stars which contribute most to the chemical enrichment of the interstellar medium
are stars which are
more massive than the Sun
At about what temperature will helium begin to fuse into carbon
100,000,000 K
The neutrino is
an elusive, subatomic particle, having very little mass,
and difficult to detect
The age of a cluster of stars can be judged by
the turnoff point on the main sequence of its H-R diagram
Why are instruments that study ultraviolet radiation put into space orbits?
The Earths atmosphere absorbs ultraviolet radiation.
How does a typical nova explosion compare with that for a supernova?
a. novas almost always occur in binary stars.
b. novas involve explosions of the surface layers.
c. novas leave behind most of the mass of the star.
d. all of the above.
e. none of the above.
a. novas almost always occur in binary stars.
b. novas involve explosions of the surface layers.
c. novas leave behind most of the mass of the star.
—> d. all of the above.
e. none of the above.
Stellar remnants with masses between 1.4 and 3 solar masses are what type of stars?
neutron stars
A planetary nebula is
ejected gases from a central star
What is the main product of helium burning in red giant stars?
carbon nuclei
A globular cluster is a group of stars
all very old, and with little of the heavy elements
A very low mass object (0.01 to 0.08 solar mass) of low luminosity is what kind of star
a brown dwarf
Which physical phenomenon keeps a white dwarf star from collapsing?
electron degeneracy or quantum crowding
In our galaxy, as time goes on, the abundance of metals
A type II supernova is produced when:
the collapse of a star’s iron nucleus causes a shock wave
that “blows off” the envelope of the star.
A white-dwarf is the likely result from which type of the following
main-sequence stars?
What is the closest location for finding material formed in a supernova explosion?
your own body
A group of thousands of very old stars with very few heavy elements is
a globular cluster
The mass of a neutron star is how many solar masses?
must be less than 3 solar masses
The crab nebula is the result of what
the result of a supernova explosion
Heavy elements which are mixed into the material from which new generations
of stars may be formed primarily come from
Which of the following properties does the neutrino NOT possess?
a. extremely small mass
b. travels at the speed of light
c. electrical charge equal to that of the electron
d. very penetrating through any matter
a. extremely small mass
b. travels at the speed of light
–> c. electrical charge equal to that of the electron
d. very penetrating through any matter
Type I supernovae occur in
binary star systems.
What is the equation for the triple alpha process?
He + He + He -> C + energy
What is the equation for the CNO cycle?
C + 4 H -> C + He + energy
What fraction of the mass of a red giant is ejected as a planetary nebula?
substantial, between 0.25 and 0.6
What method can provide direct information about the behavior of stars
beneath their surfaces?
neutrino astronomy
Helium flash refers to
the runaway helium fusion in the core of a low mass red giant star
Where in the Universe would you look for a protostar?
in dense dust and gas clouds
Which of the following are NOT very young stars or pre-stellar objects

a. infra-red emitting stars in gas and dust clouds
b. T Tauri stars
c. protostars
d. red giants

a. infra-red emitting stars in gas and dust clouds
b. T Tauri stars
c. protostars
–> d. red giants
How are elements with nuclei heavier than iron produced?
they are produced during supernova explosions
A T Tauri star is at what stage of its stellar evolution?
very early stages, just after protostar formation
Most of the energy of a supernova explosion is carried away by
Stars are formed from interstellar matter. Why then are stars in globular
clusters metal-poor, while stars in open clusters are metal-rich?
because stellar evolution and supernova explosions increase
heavy metal concentrations steadily with time
A supernova explosion produces what kind of metals?
produces heavy nuclei all the way up to uranium and thorium.
The mass limit of 1.4 solar masses is known as
the Chandrasekhar limit
What kind of star masses are the oldest?
globular cluster
The characteristics of red supergiant stars are
brightness of about 10,000 Suns and a diameter of about
Mars orbit
What type of star did the Hubble Space Telescope find many examples of
in the globular cluster M4?
white dwarfs
The one characteristic shared by all white dwarf stars without binary
companions is that
they have ceased to generate energy by thermonuclear processes
or gravitational contraction, and are cooling down
Which type of Supernova would typically occur soonest after the birth of a star?
type II
What surface surrounding a binary star system defines the boundaries of gravitational
influence of each star?
Roche Lobe
On the diagram above, identify region A
red giant stars
Identify region B
blue giant stars
Identify region C
the main sequence
Identify region D
white dwarfs
Identify region E
red dwarfs
The Crab Nebula is
a supernova remnant
A white dwarf star is about the same size as
the Earth
By about how much does a star’s luminosity increase during a typical supernova
The sun will eventually become
a white dwarf
How may Roche Lobes are there in a binary star system?
What is the name given to a star-like object that never burned hydrogen?
Brown dwarf
What type of star is Sirius B?
White dwarf
In what year did that most recent supernova visible to the naked eye appear in
the sky?
What fraction of the Suns mass is required for a collapsing system to form
a star?
0.08 or 8%
In what astronomical body in the sky did SN1987A appear?
Large Magellanic Cloud
What type of star is often found at the center of a planetary nebula?
White dwarf
There is a mass limit for a star in the white dwarf phase, the Chandrasekhar
limit, beyond which the star can no longer support itself against its own weight.
What is the value of this mass limit, in terms of solar mass?
1.4 Solar Masses

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