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California State University - Chico
California State University - Chico
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the systematic study of the properties and evolution of stars, galaxies, and the universe
Kepler proposed that..
planets move in elliptical orbits
An astronomical unit (A.U.) is defined as...
the distance between the earth and sun
Aristarchus used the size of the earth's shadow to compute...
the distance to the Moon
A cosmology with the earth at the center of the universe
Kepler's 3rd law states that...
there is a relationship between a planet's sidereal period and distance from the sun.
Ancient astronomers considered planets different from stars because...
planets move through the stars on the celestial spheres
In Chico at local noon on the autumnal equinox the sun was
The approximate angular diameter of the sun is...
Erastosthenes used the altitude of the sun in Alexandria and Syene to compute the...
mass of the earth
With respect to the stars on the celestial sphere the sun...
moves west to east
The Moon= magnitude of -12 while Sirius= -1.5. The ratio of light energy received by your eye between the Moon and Sirius is about
In the original Copernican model of the solar system...
the earth orbits the sun on a circular orbit
By the year 100 BC astronomers had a reasonable understanding of many thing. They DIDN'T know..
the mass of the earth
The path of the sun on the celestial sphere is known as the
Mars at opposition rises at...
Four proofs Aristotle used to demonstrate the earth is spherical...
1. During lunar eclipse, the shadow on the moon is round. 2.
Occam's Razor and how it is applied in the physical sciences...
recommends selecting the competing hypothesis that makes the fewest new assumptions (aka postulates, entities) when the hypotheses be equal in other respects
Phases of the moon. (new, 1st, full, and 3rd quarters) Also time and day the moon sets
Accomplishments of Hipparchus...
-discovered the star catalog with 850 stars -calculated the length of a year in about 7 mins
Observations made by Galileo that supported the Copernican model...
-saw sunspots using the telescope -jupiter has 4 moons so the earth is not in the center
Aristotelian concepts about the physical world that were accepted until the 16th to 17th centuries...
-cosmos are "perfect"
the semi circle passing through the north and south, divides the celestial sphere in half
the point directly overhead, center of the dome
angle of a star ABOVE horizon, in degrees
angle measured from North along the horizon, measured in degrees (polaris=0 degrees)
projection of earth's equator onto the celestial sphere, half way
(astronomers use) how many degrees from celestial equator
the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system
What star do all the stars in the sky appear to rotate around?
What constellation is "the house" in?
What asterism outlines Bootes?
Three stars in the summer triangle...
vega, deneb, altair
motion of Earth about its axis
motion of Earth around the sun
Each day the Earth revolves approximately how many degrees around the sun?
In one hour the Earth rotates through how many degrees?
how many cycles of waves per second
mathematical formula which gives frequency in terms of wavelength and the speed of light
frequency x wavelenth = speed of light
Which color has the LONGEST wavelength?
Which color has the HIGHEST frequency?
When wavelength goes up, frequency....
hot solid @ hot high pressure gas, ordinary light bulbs have this!
According to the relation of color and temperature, what color do hot and cool stars have?
Hot stars are BLUE
Cold stars are RED
hot gas @ low pressure
pass a continuous spectrum through a low pressure gas
How did astronomers prove August Comte ("the one thing that man will never know is the chemical composition of stars") wrong?
by looking at the spectrum!----from the pattern of emission or absorption lines, we know the chemical composition of the gas(es) in the star's atmosphere
The color of a star is determined by the star's __________.
From the type of spectrum, astronomers can learn whether the ____________ in the gas is high or low.
Which main sequence spectral type is the hottest?
Which main sequence spectral type is the coolest?
Do all main sequence stars have the same chemical composition?
What is the most abundant element in the atmosphere?
What is the SECOND most abundant element?
What type of spectrum do the WOLF-RAYET (WN) stars have?
Which spectral type has the strongest balmer lines?
When an atom with the electron in the n=1 orbit is ionized, the electron jumps from the n=1 orbit to....
The electron in the hydrogen atom must be in which orbit in order to produce Balmer absorption lines?
___________ determines KE (kinetic energy)
Kinetic energy determines _______________.
the orbit the electron is in
The orbit the electron is in determines.....
the strength of the Balmer lines.
What can happen to a molecule like CH (which causes the G band) when an atom with a large kinetic energy bumps into it??
BROKEN BOND! no longer a molecule
Why are molecules present in the atmosphere of cool M stars but not in the atmosphere of hot O stars?
because the kinetic energy isn't great enough to break the bond
Which stellar spectral type has the most electrons in the hydrogen atom in the second orbit?
Which stellar spectral type has the most electrons in the hydrogen atom in the first orbit?
Which stellar spectral type has the most electrons in either higher orbits or free of the hydrogen atom?
Which of the three variables--pressure, temperature, or density---determines which orbit the electron will be in?
Explain why the Balmer absorption lines in an A star spectrum are stronger than the Balmer absorption lines in the spectrum of an M star.
Because it has a lot of electrons in the n=2 orbit.
pulls gas and dust clouds together to form stars and liberates gravitational potential energy as the cloud collapses.
controls the THERMAL SPEED of atoms and molecules and OPPOSES star formation.
slows DOWN the collapse of the cloud and ultimately after pressure counterbalances gravity, the cloud STOPS collapsing
and their number density control the pressure within the cloud
In the Protostar stage..
the cloud is so COLD that it is dark and ONLY EMITS IR
what force makes the cloud collapse?
what is the energy source for Protostars?
As the cloud collapses... the temperature of the core _____ and the pressure________ and the rate of the collapse________.
goes UP, goes UP, DECREASES
In the T-Tauri stage...
the cloud is hot enough to emit visible radiation
what is the energy source for T-Tauri stars?
As the T Tauri star collapses... temperature _______
What is the primary reason that fusion does NOT occur in Protostars and T Tauri stars?
atoms are not close enough together because the temperature is too LOW.
"like" charges (two protons) _________ and "opposite" charges (an electron and a proton) _________
in the fusion reaction protons are pushed together. when the distance between two protons becomes LESS than 2x10^-15m, they ___________.
what force makes is difficult to push two protons together?
What controls the speed of protons in stars?
Fusion 4H---->He + energy is occurring in main sequence stars, because the temperature in the core equals....
10 million K.
What element is being manufactured in the core of main sequence stars?
What is the fuel for the fusion reaction?
When the temperature in the core reaches 100 million K, the star moves to stage IV also known as...
the RED GIANT stage
________brings heat and new elements to the surface.
__________carry new elements from the surface into space.
What happens to a gas when it is heated?
Red giants make WHICH elements?
all heavier than He up to and including Fe (iron).
Three forces that control stellar evolution are...
gravity, electric force, nuclear force
three energy sources for stars...
gravity, nuclear, thermal
What is the energy source for WHITE DWARFS?
Name the two most important variables involved in stellar evolution:
temperature and mass
What type of spectrum does the sun have?
Will the spectra of stars in globular clusters be rich or poor in absorption lines due to elements heavier than helium?
your blood contains iron. where was this originally made?
your body is mostly water. where was the hydrogen in your water originally made from?
The VIRGO cluster
in the direction of "virgo", but WAY beyond our galaxy
the HERCULES cluster
smaller, further away..
maximum wavelength of our sun is WHAT color?
as stars get hotter, max wavelength gets.....
Pauli-exclusion principle says...
you can only cram stuff in so close together
the force of gravity is related to the masses and distance between the them, (as two objects get CLOSER, the force of gravity goes UP)
Angular distance is used to figure out how far away something is. (only works for nearby stars) angle,side,angle can determine distance
as the temperature gets BIGGER, the wavelength gets SMALLER (wien's law)
Heats up.... gives off MORE energy. higher temperature, higher energy
Distance + luminosity(brightness) = determines the energy
brighter & closer means MORE energy
luminosity is related to how BIG and how HOT. bigger+hotter=BRIGHTER
if you know the wavelength and the frequency, you will get the speed of light
energy of light is related to its frequency. MORE waves that go by (higher frequency) = MORE energy
mass gets BIGGER, star gets BRIGHTER. brighter lives are shorter lives!
oh bee, a fine girl kissed me!
About 2/3 of all chemical elements have been observed in the solar spectrum. The elements other than hydrogen and helium observed in the solar spectrum
... were produced in other stars.
A K Giant such as Arcturus star may have a temperature of around 4500 K whilst a Supergiant such as Polaris is about 7500 K. Arcturus will...
appear redder than Polaris
In order to determine the luminosity of a star we need to know
the distance of the star
Ionization refers to
the removal of electrons from an atom
Jupiter orbits the Sun at about 5 A.U. Jupiter receives how much less flux from the Sun than the Earth?
about 25 times
Light from a hot low pressure gas gives
an emission line spectrum
The wavelength of the photon an atom emits depends only on...
the difference in energy of the initial and final orbits
We see what type of spectrum from most stars?
In a Main Sequence star, pressure is balanced by
Fusion is the process where
atomic nuclei merge together to form new elements
The approximate diameter of a Main Sequence star is
Star A has a parallax of .05" and Star B has a parallax of .15". From this information we say that
Star A is three times farther than B
The element with the simplest atomic structure is
The expected main sequence lifetime of the sun is
All main sequence stars have this in common
Describe a way to determine the radius of a star.
If you know how bright the star is (luminosity), and how hot the star is, you can determine the radius!
What is the ultimate fate of a high mass star?
What is the ultimate fate of a low mass star?
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