Birth and Death of StarsBirth and Death of Stars

The Life Cycle of StarsThe Life Cycle of Stars

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: 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