1. Birth and Death of Stars
The Life Cycle of Stars
28.3 page 628 :

2. The Hertzsprung-Russell diagram isn’t just an orginazational chart for the the stars, but the LIFE CYCLE of the stars!

4. You will be given the Title of the ‘last chapter’ in the life story of your star.
You will need to complete the story of a star with a Flipbook that shows a diagram and description for….
Beginning of the story: how they started (mass)
Name, description and diagram of each stage of life they go through (expansions/contractions).
Record the amount of time spent in each stage under the diagram.
You must use at least one page for each different fuel used in the main sequence.
Epilogue or sequel to their life story?
Each book will have a minimum of 8 pages (2 per partner). One person will do mass, 2 for birth, 1 for death and EVERYONE will do a main sequence page.

5. The Final Chapter of a Star Story Options (go backwards in the Star’s life cycle!)
Helpful Resources for you to use:
Google: aspire life cycle of stars
Game
classzone.com ES2807
Text book page 626
Gas Giant Planet (google with Star Life Cycle)
Brown Dwarf
Black Dwarf (low mass stars)
White Dwarf (medium mass stars)
Neutron star
Pulsar
Black hole

6. Websites
Google: aspire life cycle of stars Game classzone.com ES2807 Text book page 626

7. Stage 1 Nebula
The space between stars is filled with gas and dust. called a nebula
99% of interstellar matter is hydrogen.
Temperature: Cool
Eventually gas “clumps” and compress

8. Life Cycle (Life Story) of Stars

9. Star Carousel
You will leave your flip books with one representative at each station
You will then have 4 minutes to learn about each phase at each station. Fill in the note sheet at each spot.

11. Stellar Careers The lives of the stars seem to be “predestined”
The MASS of a star determines …
what type of star it will be,
where it will be on the main sequence, and
how long it will live for.
What it will end up as at its death
Each type of star has a particular series of events during their lifetime.
Deaths can be spectacular!

12. The MASS of a star determines … what it will be

13. Life Cycle of a Star
Death/old
young
nebula
nebula
nebula
nebula

14. Whatever the cause, the nebula begins to contract.
As the nebula collapses, the temperature and density increase.
As it contracts, it breaks into many clumps, which forms hundreds of stars of various masses.
The size of each clump determines the mass of the star that will form.

15. Joseph Howard

16. Clumps / fragmentation
These will become STARS

17. Stage 2 Protostar Still shrinking, getting denser
Temperatures increase
Core is contracting
Recognizable as a ‘star’
Has a photosphere surface

18. Life Cycle of a Star Death/old young protostar nebula protostar

19. “Duds” or Failed Stars
Clumps without enough mass are too small to become stars
They just cool and compact to become brown dwarfs orbiting in space
Gas Giant planet Jupiter is a failed star.

20. Life Cycle of a Star Not enough mass to reach temps to fuse hydrogen
Death/old
young
Brown
dwarf
protostar
nebula
Not enough mass to reach temps to fuse hydrogen
“dud”
Gas giant planet: Jupiter

21. Stage 3 A Star is Born! Gravity continues to compress the gas
When the core reaches 10,000,000 K
Nuclear FUSION begins
Hydrogen fuel is fusing into helium
A true star

22. IF the protostar has enough temperature and luminosity to make it onto the H-R scale.
Its mass determines where it jumps on.

23. 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

24. Main Sequence at Last It reaches Equilibrium: its stable
The heat & pressure of the gas expanding outward balances
the GRAVITY that is
pulling the matter inward

25. Life Cycle of a Star fuse hydrogen fuel 100 billion yrs. Main sequence
Death/old
young
Brown
dwarf
protostar
nebula
Not enough mass to reach temps for fusion of hydrogen
Gas giant planet:
Jupiter
Main sequence
STAR
fuse hydrogen fuel
100 billion yrs.
Small star will burn their fuel slowly for 100 million years!

26. 5000 lbs. mass 25 gallon gas tank 9 mpg
Which will travel a farther, longer distance? Which will burn through its fuel at a faster rate?
5000 lbs. mass 25 gallon gas tank 9 mpg
225 miles / 60mph = 3.75 hrs.
3000 lbs. weight
12.5 gallon gas tank
108 mpg
1350 miles / 30 mph = 45 hrs.

27. Death of a Star

28. Life Cycle of a Star Death/old young Brown dwarf protostar nebula
Not enough mass to reach temps for fusion of hydrogen
Gas giant planet: Jupiter”
Main sequence star
100 billion yrs.
white dwarf black dwarf
Fusing hydrogen for fuel

29. Life Span
Massive stars use up their fuel faster, so they spend only millions of years as a main sequence
The smaller mass stars spend
100 billions years as a main sequence star!

30. Stage 4: Running on Empty
Star is aging, hydrogen fuel is used up, and helium is building up in the core.
There is no heat to push out so gravity pushes in, the core becomes unbalanced and begins to collapse
As it collapses, temperature increase until it reaches 100,000,000 K!
Helium begins to fuse.
Heat generated in the core, It EXPANDS

31. The outer layers are expanding and COOL
It is now a RED GIANT
Star begins leaving the main sequence
It starts to become UNSTABLE

32. Leaving the Main Sequence
It’s a
RED GIANT
It is cooler,
but bigger,
so it’s brighter

33. Stage 5 Planetary Nebula
Core continues fusion of helium.
When helium fuel is gone, the core shrinks
Outer gas layers are thrown-off as a
Planetary Nebula
Example: Planetary Nebula IC 418

34. Stage 6: The End
Red Giant
All that is left is the core
White Dwarf

35. White Dwarf All 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.

36. Life Cycle of a Star Death/old young Brown dwarf protostar nebula
Not enough mass to reach temps for fusion of hydrogen
“dud”
Main sequence
star
white dwarf black dwarf
Fusing hydrogen for fuel
Red giant planetary white dwarf Black
10 billion yrs nebula dwarf
Hydrogen fuel fusing helium fusing
Main sequence

37. Red Super Giants Example: Betelgeuse
In MASSIVE stars, when the helium is fusing, temps increase, it expands, and becomes a SUPER RED GIANT and cools
Gravity contracts the core until its heated enough to begin burning the next element, CARBON.
This process continues through the fusing of oxygen, neon, nickel, and silicon with the high mass star alternating between the blue giant phase and the red giant phase throughout.
Large stars repeat this expansion and contraction cycle up to 7 times as their core elements keep fusing until they reach iron.
When the core becomes iron fusion ends
Example: Betelgeuse

38. Supernova VERY MASSIVE stars: > 8 M
Supernova remnant
Supernova
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!
Crab Nebula, remnant of a supernova that exploded in 1054 A.D.
most astounding fact

39. Final Stage for Massive Stars (Neutron Star or Black Hole)
Stars less than 8 solar masses become dwarf stars (cool, dim, burnt out)
Stars 8 solar masses or greater become neutron stars or black holes
Neutron Star Black Hole

40. Neutron Star
When the iron core of a MASSIVE STAR is collapsing, it might stop. Leaving behind an extremely small, dense neutron star.
Extreme density 1018 kg/m3
Extremely small: size of a city
Spin! Can emit a beam and pulse: Pulsar

41. Life Cycle of a Star
Death/old
young
Brown
dwarf
protostar
nebula
Not enough mass to reach temps for fusion of hydrogen
Gas planet Jupiter
Main sequence
100 billion yrs
white dwarf black dwarf
Fusing hydrogen for fuel
Red giant planetary white dwarf black
10 billion yrs nebula dwarf
Hydrogen fuel fusing helium fusing
Main sequence
Notice PATTERNS in the increasing mass of stars: in the years they live, the number of elements fused, the amount of energy they have at the end etc.
Neutron
Star/ Pulsars
Black
hole
Main sequence Super red Supernova!
2-100 million yrs Giant explosion
Hydrogen – helium – carbon- neon – oxygen - silicon …iron

42. Where do the ELEMENTS that were fused in the star go???
They get “recycled” back into the universe to become new stars, solar systems, planets
most astounding fact

44. The END - Death Stars iMovie
Name of final object
Starting Mass
Time / Age / years
Description
Picture / Image
Name of a familiar star as an example