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Birth and Death of StarsBirth and Death of Stars
The Life Cycle of StarsThe Life Cycle of Stars
28.3 page 62828.3 page 628
: http://outreach.physics.utah.edu/Labs/StarLife/starlife_main.html
The Hertzsprung-Russell diagram isn’t just an orginazational chart for the the stars, but the life cycle of the stars!
Very Low Mass
Birth stellar life death
Years: Fuel:
Years: Fuel:
Years: Fuel:
Life Cycle of Stars
http://mail.colonial.net/http://mail.colonial.net/~hkaiter/~hkaiter/life_cycle_of_a_star.htmlife_cycle_of_a_star.htm
Stellar CareersStellar Careers
The lives of the stars seem to be “The lives of the stars seem to be “predestinedpredestined””
The The MASSMASS of a star determines … of a star determines …– what what typetype of star it will be, of star it will be,
– wherewhere it will be on the main sequence, and it will be on the main sequence, and
– how how longlong it will live for. it will live for.
– What it will end up as at What it will end up as at its deathits death
Each type of star has a particular Each type of star has a particular series of series of eventsevents during their lifetime. during their lifetime.
Deaths can be spectacular!Deaths can be spectacular!
The MASS of a star determines …what it will be
Stage 1 Stage 1 NebulaNebula
The space between stars is The space between stars is filled with gas and dust. filled with gas and dust. called a called a nebulanebula
99% of interstellar matter is 99% of interstellar matter is hydrogen.hydrogen.
TemperatureTemperature: Cool: Cool
Eventually gas “Eventually gas “clumpsclumps” and ” and compress compress
Learn the full life cycle of a star in this internet tutorial. Go to the following website. READ the text, view all the animations take the quizzes and answer all the questions on the tutorial: http://outreach.physics.utah.edu/labs/star_life/starlife_main.html Directions: 1. Inside each box label the name of each step in the star’s life cycle. 2. Label the line across the top to indicate: Star Birth, Star Stage, Star Death.
3. Add arrows on the line to indicate the time span for each stage.
Very Low Mass
Life Cycle of a Star
nebula
youngDeath/old
Whatever the cause, the nebula begins to Whatever the cause, the nebula begins to contract.contract.As the nebula collapses, the As the nebula collapses, the temperature temperature and density increase.and density increase.As it contracts, it breaks into many As it contracts, it breaks into many clumpsclumps, , which forms hundreds of stars of various which forms hundreds of stars of various masses.masses.The The size of each clump determines the size of each clump determines the massmass of the star that will form. of the star that will form.
Joseph Howard
Clumps / fragmentationClumps / fragmentation
These will become These will become STARSSTARS
Stage 2 Stage 2 Protostar Protostar Still Still shrinkingshrinking, getting , getting denserdenser
Temperatures increaseTemperatures increase
Core is contractingCore is contracting
Recognizable as a ‘star’Recognizable as a ‘star’
Has a Has a photospherephotosphere surface surface
Learn the full life cycle of a star in this internet tutorial. Go to the following website. READ the text, view all the animations take the quizzes and answer all the questions on the tutorial: http://outreach.physics.utah.edu/labs/star_life/starlife_main.html Directions: 1. Inside each box label the name of each step in the star’s life cycle. 2. Label the line across the top to indicate: Star Birth, Star Stage, Star Death.
3. Add arrows on the line to indicate the time span for each stage.
Very Low Mass
Life Cycle of a Star
nebula
youngDeath/old
protostar
““Duds” or Failed StarsDuds” or Failed Stars
Clumps without enough mass are too Clumps without enough mass are too small to become starssmall to become stars
They just cool and compact to become They just cool and compact to become brown dwarfs orbiting in spaceorbiting in space
Gas Giant planet Jupiter is a failed star.
Learn the full life cycle of a star in this internet tutorial. Go to the following website. READ the text, view all the animations take the quizzes and answer all the questions on the tutorial: http://outreach.physics.utah.edu/labs/star_life/starlife_main.html Directions: 1. Inside each box label the name of each step in the star’s life cycle. 2. Label the line across the top to indicate: Star Birth, Star Stage, Star Death.
3. Add arrows on the line to indicate the time span for each stage.
Very Low Mass
Life Cycle of a Star
nebula
youngDeath/old
protostar
Not enough mass to reach temps to fuse hydrogen
Browndwarf
“dud”Gas giant planet: Jupiter
IF the protostar has IF the protostar has enough temperature enough temperature and luminosity to and luminosity to make it onto the H-R make it onto the H-R scale.scale.
Its mass determines Its mass determines where it jumps on.where it jumps on.
http://outreach.physics.utah.edu/labs/star_life/support/HR_animated_real.html
Stage 3 Stage 3 A Star A Star is Born!is Born!
When the core reaches When the core reaches 10,000,000 K10,000,000 K
Nuclear Nuclear FUSIONFUSION begins begins
Hydrogen fuel is fusing into helium Hydrogen fuel is fusing into helium
A true starA true star
Learn the full life cycle of a star in this internet tutorial. Go to the following website. READ the text, view all the animations take the quizzes and answer all the questions on the tutorial: http://outreach.physics.utah.edu/labs/star_life/starlife_main.html Directions: 1. Inside each box label the name of each step in the star’s life cycle. 2. Label the line across the top to indicate: Star Birth, Star Stage, Star Death.
3. Add arrows on the line to indicate the time span for each stage.
Very Low Mass
Life Cycle of a Star
nebula
youngDeath/old
protostar
Not enough mass to reach temps for fusion of hydrogen
Browndwarf
Gas giant planet: Jupiter
Main sequencestar fuse hydrogen fuel
100 billion yrs.
Main Sequence,
Hydrogen is fusing into helium
A star spends 90% of it’s life as a main sequence star.
This is it’s mature, adult stage.
Our Sun will be here for 10 billion years
Main Sequence at LastMain Sequence at LastIt reaches It reaches Equilibrium: Equilibrium: its its stablestable
The heat & pressure of the gas expanding outward The heat & pressure of the gas expanding outward balances balances
the GRAVITY that is the GRAVITY that is pulling the matter inwardpulling the matter inward
Death of a StarDeath of a Star
Life Span
Massive stars use up their fuel faster, so they spend less than a 1 billion years as a main sequence
The smaller mass stars spend 100 billions years as a main sequence star!
Learn the full life cycle of a star in this internet tutorial. Go to the following website. READ the text, view all the animations take the quizzes and answer all the questions on the tutorial: http://outreach.physics.utah.edu/labs/star_life/starlife_main.html Directions: 1. Inside each box label the name of each step in the star’s life cycle. 2. Label the line across the top to indicate: Star Birth, Star Stage, Star Death.
3. Add arrows on the line to indicate the time span for each stage.
Very Low Mass
Life Cycle of a Star
nebula
youngDeath/old
protostar
Not enough mass to reach temps for fusion of hydrogen
Browndwarf
Gas giant planet: Jupiter”
Main sequence star
100 billion yrs.
white dwarf black dwarfFusing hydrogen for fuel
Stage 4: Running on EmptyStage 4: Running on EmptyStar is aging, Star is aging, hydrogen fuel is used uphydrogen fuel is used up, , and and helium helium is building up in the core.is building up in the core.
There is no heat to push out so gravity pushes in, the There is no heat to push out so gravity pushes in, the core becomes unbalanced core becomes unbalanced and begins to collapse and begins to collapse
As As it collapses, temperature increase it collapses, temperature increase until it reaches until it reaches 100,000,000 K!100,000,000 K!
Helium begins to fuseHelium begins to fuse..
Heat generated in the core, It Heat generated in the core, It EXPANDSEXPANDS
The outer layers are expanding and coolingThe outer layers are expanding and cooling
It is now a It is now a RED GIANTStar begins leaving the main sequenceStar begins leaving the main sequence
• Leaving the Leaving the Main SequenceMain Sequence
• It’s a It’s a • RED GIANT• It is cooler, It is cooler,
but bigger, but bigger,
so it’s brighterso it’s brighter
Stage 5 Stage 5 Planetary Nebula Planetary Nebula
Core continues fusion of helium.Core continues fusion of helium.
When helium fuel is gone, the core shrinks When helium fuel is gone, the core shrinks
Outer gas Outer gas layers are thrown-off layers are thrown-off as aas a
Planetary NebulaPlanetary Nebula
Example: Planetary Nebula IC 418Example: Planetary Nebula IC 418
Stage 6:Stage 6:The EndThe End
All that is left is the core
White Dwarf
Red Giant
White DwarfAll that’s left is the core:
very small (earth size), very dense (200 x’s more dense than Earth!), very HOT (100,000 K) core
It will slowly cool over a billion years.
Learn the full life cycle of a star in this internet tutorial. Go to the following website. READ the text, view all the animations take the quizzes and answer all the questions on the tutorial: http://outreach.physics.utah.edu/labs/star_life/starlife_main.html Directions: 1. Inside each box label the name of each step in the star’s life cycle. 2. Label the line across the top to indicate: Star Birth, Star Stage, Star Death.
3. Add arrows on the line to indicate the time span for each stage.
Very Low Mass
Life Cycle of a Star
nebula
youngDeath/old
protostar
Not enough mass to reach temps for fusion of hydrogen
Browndwarf
“dud”
Main sequence white dwarf black dwarfFusing hydrogen for fuel
Main sequence Red giant planetary white dwarf Black 10 billion yrs nebula dwarf
Hydrogen fuel fusing helium fusing
Red Super GiantsRed Super GiantsWhen the When the helium is fusinghelium is fusing, , temps increasetemps increase, , it expandsit expands, and , and becomes a super red giant and coolsbecomes a super red giant and cools
Gravity contracts the core until its heated enough to begin burning Gravity contracts the core until its heated enough to begin burning the next element, carbon.the next element, carbon.
This process continues through the This process continues through the fusing of oxygen, neon, nickel, fusing of oxygen, neon, nickel, and siliconand silicon with the high mass star alternating between the blue with the high mass star alternating between the blue giant phase and the red giant phase throughout.giant phase and the red giant phase throughout.
Large stars Large stars repeat this expansion and contraction cycle up to 7 repeat this expansion and contraction cycle up to 7 times as their core elements keep fusing until they reach iron.times as their core elements keep fusing until they reach iron.
When the core becomes iron fusion endsWhen the core becomes iron fusion ends
Example: BetelgeuseExample: Betelgeuse
SupernovaSupernova Supernova remnant
Crab Nebula, remnant of a supernova that exploded in 1054 A.D.
VERY MASSIVE stars: > 8 M
When core collapses, density reaches astonishing 400,000,000,000,000 g/cm3
The core ‘overshoots’ its equilibrium point and rapidly ‘rebounds’
Core explodes in a high speed shockwave, blasting everything into space!
http://www.maniacworld.com/Crab-Supernova-Explosion.html
https://www.youtube.com/watch?v=9D05ej8u-gU most astounding fact
Final Stage for Massive StarsFinal Stage for Massive Stars(Neutron Star or Black Hole)(Neutron Star or Black Hole)
Stars less than 8 solar masses become dwarf stars Stars less than 8 solar masses become dwarf stars (cool, dim, burnt out)(cool, dim, burnt out)
Stars 8 solar masses or greater become neutron stars or Stars 8 solar masses or greater become neutron stars or black holesblack holes
Neutron StarNeutron Star Black Hole Black Hole
Neutron StarNeutron Star When the iron core of a When the iron core of a MASSIVE STAR MASSIVE STAR is is
collapsing, it might stop. Leaving behind an collapsing, it might stop. Leaving behind an extremely small, dense extremely small, dense neutron starneutron star..
Extreme density Extreme density 10101818 kg/m3 kg/m3 Extremely smallExtremely small: size of a city: size of a city Spin! Spin! Can emit a beam and pulse: Can emit a beam and pulse: PulsarPulsar
Learn the full life cycle of a star in this internet tutorial. Go to the following website. READ the text, view all the animations take the quizzes and answer all the questions on the tutorial: http://outreach.physics.utah.edu/labs/star_life/starlife_main.html Directions: 1. Inside each box label the name of each step in the star’s life cycle. 2. Label the line across the top to indicate: Star Birth, Star Stage, Star Death.
3. Add arrows on the line to indicate the time span for each stage.
Very Low Mass
Life Cycle of a Star
nebula
youngDeath/old
protostar
Not enough mass to reach temps for fusion of hydrogen
Browndwarf
Gas planet Jupiter
Main sequence 100 billion yrs
white dwarf black dwarfFusing hydrogen for fuel
Main sequence Red giant planetary white dwarf black 10 billion yrs nebula dwarf
Hydrogen fuel fusing helium fusing
Main sequence Super red Supernova! 2-100 million yrs. giant
Neutron Star
Blackhole
Hydrogen – helium – carbon- neon – oxygen - silicon …
The END - Death StarsiMovie
Name of final object
Starting Mass
Time / Age / years
Description
Picture / Image
Name of a familiar star as an example
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