Exam 3
Astronomy 1101 with Corwin at University of Charlotte
About this deck
By: Allison Northrup
Created: 2010-11-17
Size: 83 flashcards
Views: 24
Created: 2010-11-17
Size: 83 flashcards
Views: 24
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Photosphere-
1st outer layer -emits radiation that we see
Chromosphere
2nd outer layer- suns lower atomosphere
Transition zone
3rd and last outer layer- temp rises dramatically
Convection Zone
material of the sun is in constant convective motion.
Radiation zone
solar energy is transported toward the surface by radiation
Core
site of powerful nuclear fusion reactions that generates the Sun's enormous energy output
List the layers from inside to out
core, radiation zone, convection zone, photosphere, chromosphere, transition zone
How hot is the solar surface?
5800 k
How hot is the solar core?
15 million k
How old is the sun
4.6 billion years
How does energy in the core eventually reach earth?
Energy leaves the core through convection until it reaches the photosphere then is carried by radiation then the fast moving particles are moved by solar wind.
What is solar wind?
the constant stream of escaping solar particles.
This happens when protons and electrons escape from the sun and move at the speed of light reaching earth and moving more slowely this constant stream is solar wind.
What is a sun spot and what causes it?
regions that are cooler, and theyre caused by cooler temperatures.
What is a flare and what is a prominence? what causes them?
caused by instabilities in the magnetic field flares are much more violent then prominences, prominences are loops or sheets of glowing gas.
Whats fuels the suns enormous energy output?
nuclear fusion, energy is caused by fusion in a sunlike start on the main sequence
What are the ingrediants in the proton- proton chain?
4 protons
What is the end result of the proton proton chain?
Helium 4 and 2 protons
What is helium 3?
2 protons and 1 nuetron
What is helium 4?
2 protons 2 neutrons
What energy is release in the proton proton chain?
gamma rays
The density and temperture in the solar corola are much higher then in the photosphere. T/F
False the density is not higher
Sunspots appear dark because they are hotter then the surrounding gas of the photosphere. T/F
False because anothing darker would be cooler
The proton-proton chain releases energy because mass is created in the process. T/F
False , because mass isnt created
Neutrinos have never been detected experimentally. T/F
False because they are there just sent into outerspace
Compared with the Earths diameter the Suns diameter is about how many times larger?
100 times larger
The sun spins on its axi roughly once a?..
month, 25 days
The time between successive sunspot maxima is about?..
a decade..the sun has a cycle of 22 years so half of it owuld be about a decade
The primary source of the suns energy is?
fusion of light nuclei to make the heavier ones
How is the stellar paralax used to measure the distance to the stars?
apparent shift of an object relative to some distant backround as the observers point of view changes
What is a red giant? Describe
The dont fuse hydrogen and helium in the core, once it stops in the core the star is dying but it is still fusing in the outer layers which is why it still hold the red color
What is a white dwarf? Describe
a dying star, small but luminious with a high surface temp.
What is the difference between absolute and apparent brightness?
apparent is how it looks from earth but absolute is the apperent brightness a star would have if it were placed at a standard distance 10 parsecs away from earth.
What info is needed to plot a star on the H-R diagram?
luminosity and surface temp
What is the main sequence?
band of stars in the H-R diagram that are confined to a fairly well- defined band from top to bottom right (low temp low luminosity)
What determines where the stars lie on the H-R diagram?
Mass
Which stars are most common in the Galaxy?
Red Dwarfs (80% of stars in universe)
Why dont we see many red dwarfs in the H-R diagram?
They are hard to see because they have low luminosity
Highmass stars start off with much more fuel than lowmass stars. Why dont high mass stars live longer?
everything with a highmass will do things much faster
Star A appears brighter than star B, as seen from earth. Therfore star A must be closer to Earth then star B. T/F
false
Red Giants are very bright because they are extremly hot. T/F
false
There are no billion year old main sequence O- or B-type stars . T/F
true
Cool stars can be very luminous if they are very
large
The mass of a star may be determined...
by studying its orbit around the bianry companion
What is the composition of interstella gas? interstellar dust?
gas- individual atoms and small molecules. mostly hydrogen
dust- clumps of atoms and molecules
How is interstellar matter distributed through space?
interstaller matter is mostly gas and distributed unevenly (nebulas)
What is emission nebula?
glowing could of hot interstellar gas
emitting bright line spectrum
What is a 21 centimenter radiation and why is it useful to astronomers?
It is a spectral emission line results from hydrogen-spin-flip process
Measures large scale structures and
Describe basic chain of events leading to a star like sun?
Interstellar cloud-massive so it contracts and forms fragments-protostars- fusion (star is born)
What is an evolutionary track?
progression throughout H-R diagram
Why do stars tend to form in groups?
bc stars form dust clouds
What critical event must occur for a protostar to become a star?
fusion
What are brown dwarfs?
stars that are not massive enough to fuse hydrogen and helium
what are open clusters?
loose irregular clustars typically contain from a few tens to a few thousands of stars- in milky way galaxy
what are globular cluasters?
spherical- millions of stars. No main sequence stars more massive than he sun. Formed long ago
Interstellar matter is quite evenly distributed throughout the Milky Way Galaxy. T/F
false
More massive stars form more rapidly. T/F
true
Most stars form as memebers of groups for clusters. T/F
true
The red glow od an emission nebula is?
produced by hydrogen gas heated to high temperatures
The interstella medium is mostly?
hydrogen, helium and heavier elements.
How long can a star like the sun keep burning hydrogen in its core?
10 billion years
WHy is the depleation of hydrogen in the core of a star such an important event?
it is the first step towards the death of a star
Roughly how big will it take the sun to evolve from the main sequence to the top of the red giant branch?
10 billion years until hydrogen is depleated
What makes an ordinary star become a red giant?
hydrogen runs out in core. Helium burning causes energy to release increasing nuclear reaction rate envelope expands and cools and becomes red giant
What is a helium flash?
when high densities and pressuires onset helium fusion and the core cannot respond quickly enough. Tempurates rise sharply causing a runaway explosion
How do stars of low mass die?/ stars of high mass die?
low mass- inner core becomes too cool to keep nuclear burning. nees to reach 600 million k
high mass- explode as a supernova either a -neutron star or - collapse and become a black hole
What is a planetary nebula? With what stage of stellar evolution is it associated with?
when a star reaches the horizontal branch and then becomes a red giant agian The core never becomes hot enough to fuse carbon and it brightens until its envelope is ejected and forms a planetary nebula
What are white dwarfs and what is their ultimate fate?
white dwarfs occur then the core becomes very small but shines brightly by only stored heat
Eventually will become a black dwarf as it continues to cool and dim
under what circumstance will a bianary star produce a nova?
a nova is produced when i white dwarf becomes explosively active and suddenly appear in the night sky. lasts for a perios of 3 days.
(extra matter from red giant wraps around white dwarf)
What occurs in a massive star to cause it to explode?
1. neutrino pressure
2. fusion of infalling material
(type 2 supernova explosion)
What are observational difference between type 1 and type 2 supernova?
type 1- very little hydrogen and light curves
type 2- hydrogen rich characteristic "plaleu" in the light curve few months after the maximum
How do the mechanism that cause Type 1 and Type 2 supernova explain their observed difference?
type 2- stellar envelope expanding and cooling as it is blown into space by a shockwave sweeping up from below
type 1- mass grows internal pressure rise. Exceeds maximum mass of 1.4 solar mass
WHat evidence do we have that many supernova have occured in our galaxy?
supernova remnants
All of the single red dwarf stars that ever formed are still on the main sequence today. T/F
true
The sun will get brighter as it begins to run out of fuel in its core. T/F
true
A planetary nebula is the disk of matter around a star that will eventually form a planetary system. T/F
false
A nova is a sudden outburst of light coming from an old main-sequence star. T/F
false
It takes less and less time to fuse heavier and heavier elements inside a high-mass star. T/F
true
In a core-collapse supernova, the outer part of the core rebounds from the inner, high-density core, destryoing the entire outer part of the star. T/F
true
Because of stellar nuleosynthesis, the spectra of old stars show more heavy elements than those of young stars. T/F
false
A white dwarf is supported by the pressure of tightly packed...?
Electrons
A star like sun will end up as a what?...
white dwarf
Nuclear fusion in the sun will..?
create elements up to and including oxygen
Most of the carbon in out bodies originated in..?
the core of a red giant star
About this deck
By: Allison Northrup
Created: 2010-11-17
Size: 83 flashcards
Views: 24
Created: 2010-11-17
Size: 83 flashcards
Views: 24
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.
“I have used this website for three exams, and I see a huge difference in my test results.”
Naj
Naj