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- California State University - Chico
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- Geoscience 105
- Taylor
- Astronomy FINAL
Astronomy FINAL
Geoscience 105 with Taylor at California State University - Chico
About this deck
By: Tina Dreher
Created: 2010-12-11
Size: 133 flashcards
Views: 413
Created: 2010-12-11
Size: 133 flashcards
Views: 413
About StudyBlue
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Astronomy
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
Geocentric
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
null
The approximate angular diameter of the sun is...
0.5 degrees
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
null
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
ecliptic
Mars at opposition rises at...
sunset
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
null
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"
meridian
the semi circle passing through the north and south, divides the celestial sphere in half
zenith
the point directly overhead, center of the dome
altitude
angle of a star ABOVE horizon, in degrees
azimuth
angle measured from North along the horizon, measured in degrees (polaris=0 degrees)
celestial equator
projection of earth's equator onto the celestial sphere, half way
declination
(astronomers use) how many degrees from celestial equator
right ascencion
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?
Polaris
What constellation is "the house" in?
Cepheus
What asterism outlines Bootes?
Kite
Three stars in the summer triangle...
vega, deneb, altair
Rotation
motion of Earth about its axis
Revolution
motion of Earth around the sun
Each day the Earth revolves approximately how many degrees around the sun?
1 degree
In one hour the Earth rotates through how many degrees?
15 degrees
Frequency
how many cycles of waves per second
mathematical formula which gives frequency in terms of wavelength and the speed of light
F=c/wL
frequency x wavelenth = speed of light
Which color has the LONGEST wavelength?
red
Which color has the HIGHEST frequency?
violet
When wavelength goes up, frequency....
goes down
Continuous Spectrum
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
Emission Spectrum
hot gas @ low pressure
Absorption Spectrum
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 __________.
temperature
From the type of spectrum, astronomers can learn whether the ____________ in the gas is high or low.
pressure
Which main sequence spectral type is the hottest?
O stars
Which main sequence spectral type is the coolest?
M stars
Do all main sequence stars have the same chemical composition?
YES.
What is the most abundant element in the atmosphere?
HYDROGEN
What is the SECOND most abundant element?
HELIUM
What type of spectrum do the WOLF-RAYET (WN) stars have?
emission
When an atom with the electron in the n=1 orbit is ionized, the electron jumps from the n=1 orbit to....
FREEDOM
The electron in the hydrogen atom must be in which orbit in order to produce Balmer absorption lines?
n=2 orbit
___________ determines KE (kinetic energy)
temperature
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 either higher orbits or free of the hydrogen atom?
O stars
Which of the three variables--pressure, temperature, or density---determines which orbit the electron will be in?
temperature
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.
Gravity
pulls gas and dust clouds together to form stars and liberates gravitational potential energy as the cloud collapses.
temperature
controls the THERMAL SPEED of atoms and molecules and OPPOSES star formation.
pressure
slows DOWN the collapse of the cloud and ultimately after pressure counterbalances gravity, the cloud STOPS collapsing
Thermal speed
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?
gravity
what is the energy source for Protostars?
gravity
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?
gravity
As the T Tauri star collapses... temperature _______
goes UP.
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) _________
repel, attract
in the fusion reaction protons are pushed together. when the distance between two protons becomes LESS than 2x10^-15m, they ___________.
stick together
what force makes is difficult to push two protons together?
ELECTRIC FORCE
What controls the speed of protons in stars?
TEMPERATURE
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?
HELIUM
What is the fuel for the fusion reaction?
HYDROGEN
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.
convection
__________carry new elements from the surface into space.
stellar winds
What happens to a gas when it is heated?
expands
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?
thermal energy
Name the two most important variables involved in stellar evolution:
temperature and mass
What type of spectrum does the sun have?
absorption
Will the spectra of stars in globular clusters be rich or poor in absorption lines due to elements heavier than helium?
POOR
your blood contains iron. where was this originally made?
red giant
your body is mostly water. where was the hydrogen in your water originally made from?
BIG BANG!
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?
GREEN
as stars get hotter, max wavelength gets.....
SMALLER
Pauli-exclusion principle says...
you can only cram stuff in so close together
F=Gm1m2
d2
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)
D(pc)= 1
π (arc-sec)
Angular distance is used to figure out how far away something is. (only works for nearby stars) angle,side,angle can determine distance
λmax= 3000
T(k)
as the temperature gets BIGGER, the wavelength gets SMALLER (wien's law)
FLUX= L
4πd2
Distance + luminosity(brightness) = determines the energy
brighter & closer means MORE energy
L=4πr2T4
luminosity is related to how BIG and how HOT. bigger+hotter=BRIGHTER
λxΓ=c
if you know the wavelength and the frequency, you will get the speed of light
E=hΓ=hc
λ
energy of light is related to its frequency. MORE waves that go by (higher frequency) = MORE energy
Tms= m x 1010yr
L
mass gets BIGGER, star gets BRIGHTER. brighter lives are shorter lives!
spectral letters
OBAFGKM
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?
Absorption
In a Main Sequence star, pressure is balanced by
gravity
Fusion is the process where
atomic nuclei merge together to form new elements
The approximate diameter of a Main Sequence star is
106 km
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
hydrogen
The expected main sequence lifetime of the sun is
1010 years
All main sequence stars have this in common
energy source
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?
black hole
What is the ultimate fate of a low mass star?
white dwarf
About this deck
By: Tina Dreher
Created: 2010-12-11
Size: 133 flashcards
Views: 413
Created: 2010-12-11
Size: 133 flashcards
Views: 413
About StudyBlue
STUDYBLUE makes things that make you better at school.
Things like online flashcards with photos and audio.
Things like personalized quizzes and friendly reminders about when (and what) to study next.
Think of it as a digital backpack™: access to all of your study materials online and on your phone.
STUDYBLUE exists to make studying efficient and effective for every student, for free. Join us.
“Simply amazing. The flash cards are smooth, there are many different types of studying tools, and there is a great search engine. I praise you on the awesomeness.”
Dennis
Dennis