Post on 04-Jan-2016
Classification
HR diagram
Star clusters
TermsLife
cycleBlack holes
Life Cycles 2
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Temperature
The star's color index is a quick way of determining its
$400
Sun
The most famous G type star is:
$600
Planetary nebula
An envelope that is ejected from a Red Giant star and
spreads about the distance of our solar system would be
called:
$800
It’s mass
What is the single most important characteristic in
determining the course of a star's evolution?
$1000Type G2 star, middle of HR diagram-average size and luminosity, end of life will be white dwarf,
only known star to support a planet with life.
Why is our star (the sun) frequently referred to as an “average” star? Compare the important
physical characteristics of the Sun with the most common types of stars.
$200
About the middle of the main sequence
On the HR Diagram, the sun lies where?
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At the top right of the diagram
Where on the H-R diagram, are red giants like Betelgeuse?
$600
In the lower left of the diagram
On the HR diagram, white dwarfs are where?
$800
White Dwarf
Stars that have masses similar to the sun but sizes similar to Earth are:
$1000
On an H-R diagram where would a protostar lie in comparison to the main sequence?
Above and to the right of the main sequence.
$200
The stars are in old age (Red Giants) and there are hundreds of thousands to millions
of stars in a cluster.
Describe globular star clusters
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Massive blue main sequence stars
The brightest stars of a young open cluster will be
$600
Red Giants
In globular clusters the brightest stars will be
$800
Why are star clusters a great way for us to study star
evolution?
Stars that are in clusters are of similar age, (also composition and distance) from Earth.
$1000
Collisions and physical interactions that can include mergers of object.
What can occur in star clusters because of the
number of stars that are close together.
$200
Brown Dwarfs
Objects which have contracted, but are too little mass to ignite nuclear reaction are called
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Red Giant
Stars that leave the main sequence because they run out of hydrogen in their cores and
eventually become white dwarfs are:
$600
Gravitation
What is the force that keeps a main sequence star from
blowing apart?
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Radiation pressure
What is the force that keeps a main sequence star from
collapsing on itself?
$1000
A star is only stable when the pull of gravity is equal to the pressure of radiation. (When balanced it is in
hydrostatic equilibrium)
Why can we say a star spends its life trying to maintain
equilibrium?
$200
The igniting of nuclear fuel at 10 millionK
What process marks the birth of a new star (protostar to an
actual star) ?
$400
Why is it hard to study the life cycle of one star?
Stars live too long to be observed from birth to death
$600It fragments into smaller clouds that form
into many stars
How does an interstellar gas cloud first begin to form
hundreds of stars
$800Once it is heated up enough, nuclear fusion
ignites and radiation pressure stabilizes.
Why does gravitational contraction halt in collapsing protostars?
$1000
Outline the process of star formation from interstellar
cloud to main sequence
An interstellar cloud is disturbed and begins to gravitationally collapse, fragments,It heats up and spins faster. When the core temperature reaches 10 mill K, nuclear fusion begins (H into He). When outward pressure equals inward pressure the star
enters the main sequence.
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Black hole
A “failed” supernova undergoes core collapse but instead of
forming a neutron star like a Type II supernova it forms a black hole.
A hypernova ends up as a
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More slowly
As a spaceship nears an event horizon, a clock on the spaceship will go more quickly or more slowly?
$600We would continue to orbit in a period of
one year because the black hole would have the same mass and therefore the same
gravitational effect.
If the sun were replaced by a one solar mass blackhole would Earth
fall in right away or would we continue to orbit in a period of one
year?
$800
Look for effects on nearby objects
How are black holes identified (“seen”)?
$1000
Event Horizon Math problem: Calculate the Scharzchild radius for the sun using the following:
R=2GM/c2
M=1.9x1030 kg
G=6.67x10-11 Nm2/kg2
C=3x108 m/sec
2.8 km
$200
Star formation may be triggered by __________which help gravity through compression of interstellar clouds to greater densities.
Shock waves from supernovae
$400
Strong winds develop during which phase of a protostar?
T Tauri
$600
When does the T Tauri star occur?
When a protostar in about to become a main sequence star
$800
Why is the largest group of stars the main sequence stars?
They are young enough to not have most of their hydrogen not fused into helium. They do not evolve off until helium is built up. Most of stars life time is spent as a main sequence star.
$1000
What are three possible outcomes of stellar evolution? Which sized stars (in solar masses) on the Main Sequence are thought to become each of these?
If <1.4 Solar masses will become a white dwarf (Red Giant throws off a planetary nebula)1.4 to 3 solar masses becomes a neutron star from a Type II supernova explosion.Above 3 solar masses becomes a black hole