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Ast1002 Final Exam Cumulative

FSU Professor Lind Final exam cumlative AST1002
STUDY
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The Solar day is longer than the sidereal day.
True. Solar day is 24hours and a sidereal day takes 3.9 more minutes.
If Earth rotated half as fast as it currently does, but its motion around the Sun stayed in same then...
The night would be twice as long
What causes the Earth's seasons?
23.5 degree tilt on Earth's rotational axis
Sidereal Day
time it takes the earth to complete one rotation as measured by the stars
Solar Day
time it takes the sun to go from noon one day to noon the next.
Retrograde motion
Earth travels faster than the other outer planets to Earth's periodically overtakes the other planets making it appear as though the other planets stop and move backwards.
A major flaw in Copernicus's model was that it still had
circular orbits
If Earth's orbit around the Sun were twice as large as it is now, the orbit would take
more than two times to traverse
One light-year
distance that light travels in one year
Galileo's observation is significant because Jupiter's satellites show that...
the observation showed that bodies can orbit an object other than Earth
Modern telescopes use mirrors rather than lenses because
large lenses are more difficult to make, large lenses can be very heavy, mirrors can be computer controlled to improve resolution & light passing through lenses can be absorbed or scattered.
The MAIN reason professional observatories are built on the highest mountain tops is...
reduce atmospheric blurring
The MAIN reason that most professional research telescopes are reflectors it that...
mirrors produce sharper images that lenses do since there is no chromatic aberration
Which hero of the Renaissance postulated three "laws" of planetary motion?
Kepler
Kepler's 1st law of planetary motion
1) planets orbit the Sun
2) orbits are elliptical in shape
3) orbits are noncircular
4) applies to all orbiting objects
Kepler's 2nd law
a planet moves faster when closer to its star
Copernican Revolution
choose a heliocentric view over a geocentric view
Galileo
1) observed the moons of Jupiter
2) observed Venus has phases
Occam's Razor
the simplest theory, is always the right answer
Ptolemaeus (Ptolemy)
constructed the best geocentric model-each planet orbits Earth, and at the same time moves in circles about that orbit
Aphelion
farthest point from the sun
Perihelion
closest point from the Sun
Kepler's 3rd Law
The square of a planet's orbital period (Earth years) is proportional to the cube of its semimajor axis (AU)
Newton's First Law of Motion
An object at rest remains at rest and a moving object continues to move forever in a straight line with constant speed, uunless some external force changes their state of motion
Newton's 2nd Law
Acceleration of an object os directly proportional to the net applied force and inversely proportional to the object's mass
Newton's 3rd Law of Motion
To every action there is an equal and opposite reaction
Let's say Earth has the same mass, but is half the radius. How does the force of gravity change?
Half the radius then, for the same mass means four times the gravity. The gravitational force is inversely proportional to the square of the distance
You throw a baseball to someone; before the ball is caught, it is temporarily in orbit around Earth's center?
true
The leading theory of solar system formation is...
The planets formed from the same flattened, swirling gas cloud that formed the Sun.
What is the number of confirmed planets beyond our solar system?
more than 300
Terrestrial planets (earth-like)
Mercury, Venus, Earth and Mars
Most asteroids are found
between Mars and Jupiter
The planet with the largest diameter in our solar system is
Jupiter
The overall shape of the orbits of most the planets
is slightly elliptical, but nearly circular
Sunlight absorbed by Earth's surface is re-emitted in the form of
infrared raditation
If Earth has no moon, then tides would
occur with the same frequency, but would not be as strong. The Sun also affects the tide but lesser than the moon.
The most likely theory of the formation of the moon is...
formed from a collision of Earth with a Mars-sized object
The region around Earth where the magnetic field traps charged particles is the...
Van allen radiation belts
Which of these gases is least abundant in our atmosphere?
hydrogen
Terrestrial planets have ______ compared to the jovian planets which has several ______
one or no moon, several/many moons
The Jovian planets have
a large number of moons
Jovian planets share
1) many moons
2) large magnetic fields
3) lots of hydrogen &helium gas
4) differential rotation
5) have much thicker
Mercury's solar day is longer than its solar year
true
Feature of Venus?
that the temperature on the surface does not change significantly between day and night
Jupiter's bright zones are cloud streams made of ___________ ice crystals.
Ammonia
Venus's surface is permanently obscured by clouds. So it has been mostly studied by...
orbiting satellits using radar
Jupiter has a large magnetosphere and strong magnetic field
This is due to the liquid metallic core
The vastly different atmospheric character of Mars is likely due to...
a reverse greenhouse effect
The most famous and long lasting storm in the solar system is Jupiter's
Red Spot
Jupiter's atmosphere is mostly
hydrogen
What effect does the greenhouse effect have on the surface environment of Venus?
to raise the surface temperature by hundreds of degrees
From Earth
Venus is brighter then Jupiter
A feature of Mars which distinguishes it from the other planets is
the dust storms
Why did the Soviet spacecraft survive for only a few minutes on the Venusian surface?
The conditions of extreme pressure, corrosive atmosphere, and high temperatures severely damage it.
The most likely explanation for the retrograde rotation of Venus is...
impact of a massive object on it early in its history
Both Jupiter and Saturn
1) emit more energy than they absorb from the Sun
2) have liquid metallic hydrogen in their interiors
3) rotate very rapidly than the terestial planets
4) have rings
The seasons on Uranus
Its strange tilt produces extreme seasonal variations
Saturn is the
least dense of the planets, and could float on water
Neptune has the Great _____ spot
Dark
Saturn's rings exist because
they lie within the planet's Roche limit
Triton's orbit is unusual because
it is retrograde
Io's surface appears very smooth bc...
is continuously by volcanic activity
The Galilean moons of Jupiter are sometimes described as a miniature inner solar system bc...
the moon's densities decreases with increasing distance from Jupiter
What future awaits Triton, the largest satellite of Neptune?
tidal breakup as it spirals closer to Neptune
What is the Dynamo theory?
The magnetic field of Earth is caused by the spinning electrically conductive metal core of the planet
Uranus and Neptune magnetic fields
are offset from the planet's centers
The formaton of Jupiter and its moons may have mimicked on
a small scale the formation of the Sun and the interior planets
Jupiter's moon's unique qualities.
Titan
Io
Europa
Triton
Titan= has nitrogen atmosphere like earth's early atmosphere
Io= has volcanic activity
Europa= appear to have water
Triton= completely doomed, within roche limit of Neptune
Reading Music Is Very Unsatisfying for Xylophones and Glockenspiels
Radio, Microwave, Infrared, Visible, Ultraviolet, X-Ray and Gammaray
What is the most abundant element in the Sun?
Hydrogen
Compared with Earth's diameter, the Sun's diameter is about...
100 times larger
What is the primary source of the Sun's energy?
fusion of light nuclei to make heavier ones
The density of the Sun is most similar to that of??
Jupiter
The proton-proton cycle involves what kind of fusion process?
hydrogen into helium
How long does it take for a photon to escape from the solar core?
about a million years
how much mass will the sun lose to space during its lifetime, through the solar wind?
a few thousandths of its total mass
What is a neutrino
an elusive, subatomic particle having little mass, difficult to detect.
To determine the radius of a star, you must know what?
luminosity and temperature
The mass of a star may be determined
by studying its orbit around a binary companion
how hot is the core of the sun?
15,000,000K
What is luminosity?
the amount of radiation (energy) leaving a star per unit of time.
What's a Giant?
starts with radii between 10-100 times that of our sun
What's a dwarf?
anything smaller in radius than our sun
What is the single most important characteristic determining the course of a star's evolution?
mass
Why is dust important to solar system formation?
1) it radiated in the infr-red which helps to cool the cloud down
2) it provides a platform on which additional material can "climp" up
The Earth has a
solid, dense, nickle-iron core
The temperature at the center of Earth is approx the
same as the surface of the sun
Seismic waves are how we learned about the
Earth's structure
Concerning the Earth's greenhouse effects...
The concentration of CO2 in the atmosphere has been increasing since the start of the industrial revolution
Which of these is the smallest of the terrestrial world?
Mercury
Mercury has the largest eccentricity of the
Terrestial worlds
Mercury has the
largest angle to the plane of the rest of the solar system
The atmosphere of Mars..
mostly nitrogen like Venus and much less dense than Earth's
What is absolute zero?
The temperature at which all thermal motion stops
Magnitude for the temperature for the center of the sun
10,000,000K
The Radiation zone is...
A region of the sun where the material is mainly ionized.
A region where photons can travel through relatively freely
As few as two wavelength measurements can be used to estimate the temperature of a star.
True
What is plotted on the HR diagram?
Luminosity and Temperature
As the distance of an object increases the parallax decreases
decreases
Red giants
are larger and cooler than our sun
What is the ultimate stage of our star
to become a black dwarf
Galaxies merging causes
star formation and destruction of spiral arms
why do typw 1 supernovae provide signposts for large distances?
they all have the same absolute luminosities
Hubble Law
relates galatic recession velocity to the distance to the galaxy in question
What is driving the expansion of the universe?
Dark energy
Nuclear fusion in the core of a massive star cannot create elements much heavier than iron.
This is true.
The Sun will get brighter as it begins to run ot of hydrogen (fuel) in its core
it begins to run ot of hydrogen (fuel) in its core
White dwarf is supported by the pressure of
tightly packed- electrons
All things
included light are attracted by gravity
What is general relativity?
The warping of space, or curving by matter.
The lighthouse model explains how...
a rotating neutron star generates an observable beam of light
most pulsars are observed as radio sources
...
What is the event horizon of a black hole?
"surface" from inside of which nothing can escape
As a spaceship's velocity gets closer to the speed of light
its length will decrease and its clock will run more slowly
Due to the density and collisions among galaxies, ___________ are rare in the centers of clusters.
spirals
Where is dark matter located?
dark matter appears to be concentrated in spherical haloes around galaxies but extends far beyond the visible matter
the diamete of the Milky Way is
30kpc
The mood has many more craters than the Earth because
The moon has no atmosphere, no liquid water on its surface, Earth Does have water on its surface.
Why does one face of our moon always point toward Earth?
Because tidal locking causes the rotation and revolution periods to be equal
One would expect that the densest part of the Earth is
The core
The magnetic field of Jupiter is probably due to
Electric currents generated by Jupiter's fast rotation and convection within liquid metallic hydrogen interior.
In order of size from largest to smallest, which is correct?
Uranus, the earth, Mars, mercury.
Which of these best separates the properties of Mercury and the Moon from the other terrestrial worlds?
They are too small to retain any substantial atmosphere
Olympus Mons, volcanic mountain is Pluto, is 700 Km across, what would its angular diameter be as seen from Earth based telescopes?
nearest 2.0 arcsecs.
The primary cause of the high temperature on the surface of Venus is
trapping of infrared solar energy by the thick clouds and CO2 in its atmosphere.
Hydrogen escaped from Earth's atmosphere because
Hydrogen is the lightest fastest atom in atmosphere's
The number of confirmed planets detected beyong our solar system is
more than 400.
How long would it take the control signals for the Cassini probe in orbit around Saturn, sent by radio beam at the speed of light to travel from mission control on the Earth to the Satellite when the two planets are at closest approach?
between 10-100 minutes. (distance/velocity)
Whih of the following statements about atmospheres in the solar system is false?
Among all the moons of the solar system, Titan's is exceptional because it is so thin and tenuous.
One property of Jupiter's and Earth's interiors which makes them similar is
both are mostly liquid and both conduct electric currents.
Of the Galilean moons of Jupiter, Callisto has a surface that is the most heavily cratered. This fact implies that, compared to the others, Callisto has the:
oldest, most unchanged surface.
Io appears to be more active geologically than the other Galilean satellites of Jupiter. This activity appears to arise from
strong heating of Io due to tidal forces
Which of the following statements comparing the terrestrial and Jovian planets is false?
Jovian planetary interiors are high density, while terrestrial planets are low density
So far, only one planet has not been visited and studied by space probes from Earth. This planet is
Pluto
Neptune's average distance from the sun is 30.06 AU. According to Keplers 3rd law, how long will it take Neptune to make one compete orbit around the sun?
approx. 164.8 years. (p^2=a^3)
Water on the Earth was
transported here by comets
What is the Roche limit?
the distance at which a moon held together by the tensile strength of rocks will be broken apart by tidal forces from the planet.
The first planet searched for and then discovered because of a mathematical prediction based on its gravitational influence was the planet
Neptune
Which of the following statements about comets is false?
The orbits of most comets which we see in the inner solar system are elongated ellipses. comet tails have been measured to be over 2AU long. Comets tails are much brighter when the comet is near the Sun. The nucleus of a comet is thought to be similar in composition to a dirty snowball.
One explanation of why planets near the Sun have so much rock and Iron compared to the outer planets is that
The sun's heat made it difficult for other more volatile substances such as ices and gases to condense near it.
Astronomers believe that many comets, especially those with tilted orbits, originate
from the Oort cloud, which is a very large distance from the Sun
Comets and asteroids are
the leftovers of the formation of the planets
Most of the following pieces of information about pluto are known only either because of the presence of its moon Charon or because of occuultation observations. Which piece of information is known so far almost entirely from observations of a series of mutual eclipses between pluto and charon that took place around 1988?
the presence and shading of surface features on Pluto
As a comet leaves the vicinity of the Sun, its ion tail points from the comet's nucleus
directly away from the sun
The streak of light produced in the sky by the vaporization of a chunk of matter
meteor
Uranus was discovered about the same time as
the US. Declaration of Independence
If the Earth had no moon, the the tides would
occur with the same frequency, but would not be quite as strong.
Venus's surface is permanently obscured by clouds. As a result, the surface has been studied by
orbiting satellites using radar.
The solar system object most similar to Pluto is
Triton
According to the best available data, the largest member of the group of worlds beyond Neptune's orbit known as Keiper belt Objects is named
Eris
Relative to the horizon, as seen from the northern hemisphere, most stars (except those near the poles) follow daily motions that:
Rise to the east set in the west
If the star Vega is 26 light years away, then
the light we see today left the star 26 years ago
Which of the following is not evidence that the Earth is round?
Edge of shadwos of lunar eclipses are always curved. Shadows cast at different places on the Earth's surface at noon on the same day have different lengths. Polaris is different heights above the horizon at different latitudes. Boats going out to sea drop below the horizon. All the above
From a city in the Northern hemisphere, what direction must you facing in to have the noonday sun directly in front of you?
South
When the Earth is lying on a line exactly between the Moon and the Sun, and close enough to cast a full shadow, we have a
total lunar eclipse
The tilt of the earth's axis causes the seasonal temperature variation on the Earth through what secondary effect?
The variation in the concentration of sunlight as it shines down at steeper or shallower angles at various times of the year. The variation in length of days.
Rank the following objects in order of size largest to smallest
Size of Milky way galaxy, one light year, distance to the sun, diameter of pluto
The path that the earth moves around the sun over time is called the
ecliptic
You look up at the sky and see the moon very low exactly toward the east and see that it is a third quarter phase. Knowing the relative positions of the earth moon and sun, find the time of day
Exactly at midnight
In which way did Copernicus' model of planetary
The Earth revolves around the sun
Navigators in the northern hemisphere can find their longitude on the Earth's surface by observing
the precise time when the zero of right ascension or a selected star of known right ascension passes across the local meridian
According to Newton, does the Earth have any gravitational influence on Mars
Yes, all the time
According to Keplers's second law, when a planet moves closer to the sun in its orbit,
it speeds up
Rank the following objects in order of size (small to large)
Diameter of the sun, distance to jupitar, one light year, Milky way galaxy
Describe the daily motion of the star Polaris?
It stays fixed in northern sky above our North Pole
The observed position of the Sun against the background of the stars changes each day because of
the revolution of the earth around the sun
As a star rises and moves across the sky, which of the following will change?
its azimuth
The primary cause of the seasonal temperature variations on the Earth is
the tilt of the Earth's axis
Navigators in the Northern Hemisphere can find their latitude on the Earth's surface by observing the angle between
the north celestial pole and the horizon
Which of the following is NOT evidence that the earth is round
During partial Solar eclipse, light scattered through leaves will cast thousands of small bright rescents on the ground.
If an observer looks up to find the Mon, and finds it high overhead straight toward the south at the same time the sun is rising, what phase is it in?
3rd quarter.
What causes Solar Eclipse?
The moon's shadow falls on a small portion of the earth
The highest high tides and lowest low tides (Called Spring tides) occur
At every new and full moon
In the Copernican model, retrograde motion
occurs when one planet, moving faster in its orbit, moves past another.
The changing phases of which planet were used by Galileo to refute Ptolemy's epicycles?
Venus
Which of the following correctly orders the radiation in the electromagnetic spectrum by wavelength?
radio waves, infrared, visible light, ultraviolet, x rays, gamma rays
The Earth's structure is differentiated, this means the least dense material makes up the ______, and the most dense as the _____
crust, core
The northern lights, referred to as the aurora borealis, are caused by
Charged particles from the sun streaming in along the Earth's magnetic field lines and striking the atmosphere near the Earth's poles
According to the Viking Orbiter results, in winter the outer parts of the Martian pole caps consist mostly of
Carbon dioxide ice
Which of these best separates mercury and the moon from the other terrestrial planets?
They are too small to retain any substantial atmostphere.
The Earth's magnetic field is probably due to
Electric currents generated by the rotation of the Earth and convection within the Earth's liquid metallic iron core
Compareing the Jovian and Terristial planets in terms of their group characteristics, which of these is NOT correct?
The Jovian planets have much higher density
The inner planets are relatively depleted in the most volatile elements because
Their constituents condensed at high temperatures
Jupiters moon IO has no observable impact craters because
Volcanic activity has covered them over
In general, the interiors of large planets cool
more slowly than small planets of similar composition
Why do we see fewer craters on the earth compared to the moon?
Plate tectonics and weathering have altered the Earth's crust, obliterating them
What is one way that the existence of Pluto's satellite Charon was verified?
The brightness of this binary system varied in a regular way.
On which of these bodies have active volcanoes NOT been observed?
Venus
The Ionic talk of comets points
along a line directly away from the sun
Kepler's second law
An imaginary line drawn from the center of the sun to the center of the planet will sweep out equal areas in equal intervals of time. (The Law of Equal Areas)
The composition of a comet most nearly resembles a
dirty snowball
On the Vernal (spring) equinox from Tallahassee, at which azimust will the sun set?
270, in the West
How many hours of sunlight are there on the Winter Solstice at the North Pole?
None
If you were at the north Pole on the Vernal Equinox, what would be the maximum altitude of the sun?
0
If you were at the North Pole on the Vernal equinox, what would be the maximum altitude of Polaris?
90
Does the sun ever reach 90 altitude in Tallahassee, Fl?
No
Why do we begin by aligning our telescope with Polaris?
Because it is located at the North Celestrial Pole.
If we were to go on a field trip to the Artic Cirtle (Latitude 66.5), what altitude should we set our telescope to so that we can align it with polaris?
66.5
If the polar axis of the telescope is pointing at the N. Celestial Pol and Polaris is in the telescope's field of view, what should the declination read?
90
After alighning the telescope with Polaris you alighned it with a guide star to enable you to set which of the following scales?
Right Ascension
Which of the following coordinates of your guide star changed during your observation?
Altitude and Azimuth
Which of the following coordinates of a star change during the night and also depend on the place of observations?
Altitude and Azimuth
Which of the following coordinates of a star remain the same, both during the night and from night to night?
Declination and Right ascension
Which of the following stars has a declination of 90?
Polaris
Which of the following coordinates specifies the angular height above the horizon?
Altitude
If you see a star that is due East, what is its Azimuth?
90
When setting up the telescope we align the its polar (or RA axis) axis with:
The direction of Polaris
Why do we take the time to align the telescopes polar axis?
Because if the telescope's polar axis is correctly alighned, the telescope only needs to be adjusted about this axis to track the moon as the Earth rotates. This can be done automaticall, and at the correct rate, using the motor on this axis.
When observing the moon, where can features such as mountains and craters be seen most clearly?
Along the terminator- the boundary between the sunlit (lunar day) and dark (lunar night) areas
What causes the changes in the image we observe through the telescope?
Concave primary mirror, mirror reflection, star diagonal reflects the light by 90, orientation of the star diagonal
Clear skies provided, which of the following stars would have been visible tonight at 9PM from Tallahassee,
Sirius, Polaris, Capella
Which of the following planets were out at 9PM
Mars and Jupitar
Which of the following nebulae were above the horizon at 9PM?
M42 Orion Nebula, M1 Crab Nebula
Which of the following galaxies and clusters were above the horizon?
M31, M51, M45,M44
Which of the following stars has a declination of 90?
Polaris
When setting up the telescope we align its RA axis with
the Direction of Polaris
Which coordinates of Jupiter did not change significantly during the course of the lab?
Right ascension and Desclination
If we wanted to know how big jupitar was, what information would we need?
Its distance and transit time
The brightest star that was visible tonight was
Sirius in Canis Major
Which of the following stars did you not observe tonight?
Vega
Which of the following stars was reddish?
Betelgeuse in Orion
Which star did not move on the sky during the entire time of the lab?
Polaris
Which of the following is a measurement of angular height above the horizon?
Altitude
The field of view of a telescope is measured in
Degrees
Why do astronomers prefer to use RA and Dec rather then altitude and azimuth?
Because the RA and Dec. of a star do not change
To do with choice of eyepiece, which of the following is correct?
To first find an object, you would use an eyepiece that gives a large field of view
Which of the following three angles is larger?
Angle A
As you approach a building the angular height of the building
increases
Which of the following statements about solar magnetic fields is false?
Granulation in the photo sphere is due to magnetic field activity
Emission spectra in the Sun's atmosphere are an indication that
The Sun's Corona is very hot
The sun is supported against the crushing force of its own gravity by
gas and radiation pressure
Antares is one of the coolest known stars. The spectral tpe is
M
Which one of the following statements about protostars is false
Protostars exist for a much shorter time than the lifetime of the same mass main sequence stars.
The visible light we see from our Sun comes from which part?
Photosphere
The Density of the Sun is most similar to that of
Jupitar
Any object will collapse under its own weight unless something stops it. In an ordinary star like the sun, this collapse is prevented by
gas pressure inside the star
What is the difference between luminosity and (energy) flux?
Luminosity is the rate at which energy is emitted from an entire object; flux is luminosity per unit area.
The number of sunspots and solar activity in general peaks
every 11 years
The Temperature in the surface of the sun is 5800k. What is the expected dominant wavelength of the sun?
500 NM
The rotation of the sun is
Fastest at the equator, slower at mid-latitudes, and slowest near the poles.
What is surprising about the atmosphere of the Sun?
The temperature of the Sun's Atmosphere, after falling above the photosphere, rises again to reach very high values high in the atmosphere
What is the explanation for the bright cells of photospheric gases that make up the cellular granulation pattern seen on the visible surface of the sun?
The cells are the tops of blobs of hot gas that have risen from the Sun's convective zone.
What two energy transport mechanisms, in order from outside the core to the surface, is found in the sun?
Radiative diffusion, convection
A loop of gas following the magnetic field lines between sunspots' poles is
a prominence
The surface of the Sun near its edge appears dimmer and cooler than at the center of the disk when viewed in visible light because we see
less deeply into the sun near the edge than at disk center and temperature increases with depth.
Spectral lines observed in the granules seen at the center of the Sun's disk are
Blue shifted near the center of the granule and redshifted near the edge of the granule.
A visible light spectrum of the Sun reveals many dark absorption lines. These lines are caused by photon absorption, which takes place in the
photosphere
The solar winds blow outward from
coronal holes
In the proton-proton cycle, the helium atam and neutrino have less mass than the original hydrogen, what happens to the lost mass?
It is converted to energy (E=mc2)
The solar wind is made up primarily of
Hydrogen nuclei and electrons, some He Nuclei.
Nuclear fusion is the
combining of light neclue (Hydrogen) to produce heavier nuclei with resultant release of energy
The core of the Sun, in which the Sun's thermonuclear energy is produced, takes up about
1/4 of the sun's radius
The Solar neutrino problem refers to the fact that astronomers
detect only one third the number of neutrinos expected by theory.
Stellar parallax is used to measure the
distance of stars
The absolute magnitude of a star is its brightness as seen from a distance of
10 parsecs.
Two stars have parallaxes of .023 arseconds, but star A has apparent magnitude 2.3, while star B is magnitude 7.3. Which statement is true?
Star A is both 100 times brighter and more luminous than star B
The key difference between the spectra of B stars and G stars is
B stars show strong hydrogen lines; G stars show weaker hydrogen lines
In general, what can be said about O and B stars compared to type K and M stars
They are hotter and younger
On the HR diagram, red supergiants like Betelguese lie,
at the top right
How can we tell that some stars are relatively close Earth in the sky?
The stars appear to move periodically back and forth against the background stars because Earth's movement around the sun.
The surface temperature of a nearby star can best be determined from spectral classification by examining the
pattern of spectral absorption lines from various atoms.
As you move upward and to the left on the HR diagram the stars become
hotter and whiter
What is spectroscopic parallax?
Distance to a star measured using the spectral luminosity class of the star and the inverse square law
Which important stellar parameter can be derived from the study of binary stars mutually bound to each other by gravitational forces?
Stellar masses
Some regions of the Milky Way's disk appear dark because
stars in that direction are obscured by interstellar dust.
When a star's visible light passes through interstellar dust, the light we see
is dimmed and reddened
Interstellar gas is composed primarily of
90% hydrogen, 9% helium, and 1% heavier elemenets
The 21-centimeter radiation is important because
its radio waves pass unaffected through clouds of interstellar dust.
All stars in a stellar cluster have roughly the same
distance
What two things are needed to create an emission nebulae?
Hot stars and interstellar gas, particularly hydrogen
The Average temperature of the typical dark dust cloud is about
100k
The single most important determinant of the temperature, density, radius, luminosity, and pace of evolution of a protostar is its
mass
The space between stars is known to contain
gas, both atomic and molecular and dust
The distinctive color of a reflection nebula is
blue, caused by the scattering of light from dust grains
What is a protostar?
Sphere of gas after collapse from an interstellar cloud but before nuclear reactions have begun
Stars like our Sun will end their lives as
White dwarfs
The sun will evolve away from the main sequence when
Helium builds up in the core, while the hydrogen-burning shell expands
The helium flash occurs
in the red giant stage
Stars gradually lose mass as they become white dwarfs during the
planetary nebula stage
A star will spend most of its "shinning" lifetime as
a main-sequence star.
As stars evolve during their main sequence lifetime
they don't change their spectral type.
Which of these does not depend on a close binary system to occur?
a type II supernova
Type II supernovae occur when their cores start making
Iron
The heaviest nuclei of all formed
in the core collapse that sets the stage for a type II supernovae
What are the main products of helium nuclear fusion in red giant stars?
Carbon and (some) oxygen nuclei
The characteristics of a red giant star are the brightess of about ____ and a diameter of ____.
1000 Suns: about Mercury's orbit
In the process of Helium shell fusion in a low mass star near the end of its life, the star moves upward and to the right on the asymptotic giant branch of the Hertzsprung-Russell diagram. In this process, the star is
expanding, cooling and becoming more luminous.
A planetary nebula is an
expanding gas shell surrounding hot, burned-out stellar core.
A white dwarf star is at what stage of its evolution?
Very late phase of evolution, no longer generating engergy.
A nova is an explosion involving a white dwarf. an a white dwarf become a nova more than once? Why or why not?
Yes, a white dwarf can become a nova more than once if it continues to receive matter from a companion star.
Measurements suggest that light first arrived at Earth from the Cassiopeia A supernova about 300 years ago and that this supernova is 10,000 light-year distant from Earth. When did the explosion actually occur?
10,300 years ago, or about 8300 BC
What is the correct evolutionary process of a normal star about fifty solar masses?
Protostar, main sequence, red super giant, supernova, black hole
The most common star are
Lower main sequence stars
A planetary Nebula is
the expelled outer envelope of a dying medium to low mass star