1. Stellar Evolution Task
Low Mass Stars
How do they evolve

2. The evolutionary path of a low mass star
Starter
Task A
The evolutionary path of a low mass star
NEXT
Sun
main sequence
Hand out
Luminosity
1 Sun
Sun
white dwarf
0.001 Sun K
2 500 K
Surface Temperature
Draw the path from main sequence to white dwarf in the
HR diagram provided on the printed hand-outs

3. What sizes can stars have
Starter
Task B
What sizes can stars have
NEXT
Jupiter
Sun
Atom
You
NTU
Nottingham
Earth km
0.002 km
1 km
10 km
6 000 km km km
Earth's
Orbit
Saturn's
Orbit
Solar
System
Next
Star
Sun
Galaxy km km km km km km
Hand out
Highlight the smallest and largest sizes of a low mass star during its evolution
on the size scale on the printed hand-out

4. Main page of low mass evolution
Redo the starter
tasks to finish
Learn more about
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Evolutionary
Speed
Size
Evolution
Colour
Change
Some Questions on
low mass evolution
Some further images and information on evolutionary stages

5. The evolutionary path of a low mass star
Starter
Task A
The evolutionary path of a low mass star
NEXT
Sun
main sequence
Hand out
Luminosity
1 Sun
Sun
white dwarf
0.001 Sun K
2 500 K
Surface Temperature
Draw the path from main sequence to white dwarf in the
HR diagram provided on the printed hand-outs

6. What sizes can stars have
Starter
Task B
What sizes can stars have
NEXT
Jupiter
Sun
Atom
You
NTU
Nottingham
Earth nm
0.002 km
1 km
10 km
6 000 km km km
Earth's
Orbit
Saturn's
Orbit
Solar
System
Next
Star
Sun
Galaxy km km km km km km
Hand out
Highlight the smallest and largest sizes of a low mass star during its evolution
on the size scale on the printed hand-out

7. That's all on low mass stellar evolution !
Stellar Evolution Task
That's all on low mass stellar evolution !

8. A low mass star in the HR diagram
Time
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Main sequence
NEXT
Play

9. A low mass star in the HR diagram
Time
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Subgiant branch
Previous
NEXT
Play

10. A low mass star in the HR diagram
Time
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Red Giant
Branch
Previous
NEXT
Play

11. A low mass star in the HR diagram
Time
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Helium
Flash
Previous
NEXT
Play

12. A low mass star in the HR diagram
Time
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Horizontal
Branch
Previous
NEXT
Play

13. A low mass star in the HR diagram
Time
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Asymptotic
Giant
Branch
Previous
NEXT
Play

14. A low mass star in the HR diagram
Time
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Planetary Nebula
Previous
NEXT
Play

15. A low mass star in the HR diagram
Time
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Previous
Return to
Main Page
Play

16. A low mass star in the HR diagram
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Size
Main sequence
NEXT
Play

17. A low mass star in the HR diagram
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Size
Subgiant branch
Previous
NEXT
Play

18. A low mass star in the HR diagram
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Red Giant
Branch
Size
Previous
NEXT
Play

19. A low mass star in the HR diagram
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Size
Helium
Flash
Previous
NEXT
Play

20. A low mass star in the HR diagram
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Size
Horizontal
Branch
Previous
NEXT
Play

21. A low mass star in the HR diagram
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Size
Asymptotic
Giant
Branch
Previous
NEXT
Play

22. A low mass star in the HR diagram
Size
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Planetary Nebula
Previous
NEXT
Play

23. A low mass star in the HR diagram
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Size
Previous
Return to
Main Page
Play

24. A low mass star in the HR diagram
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Colour
Main sequence
NEXT
Play

25. A low mass star in the HR diagram
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Colour
Subgiant branch
Previous
NEXT
Play

26. A low mass star in the HR diagram
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Red Giant
Branch
Colour
Previous
NEXT
Play

27. A low mass star in the HR diagram
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Helium
Flash
Colour
Previous
NEXT
Play

28. A low mass star in the HR diagram
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Horizontal
Branch
Colour
Previous
NEXT
Play

29. A low mass star in the HR diagram
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Asymptotic
Giant
Branch
Colour
Previous
NEXT
Play

30. A low mass star in the HR diagram
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Planetary Nebula
Colour
Previous
NEXT
Play

31. A low mass star in the HR diagram
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Colour
Previous
Return to
Main Page
Play

32. Stellar evolution low mass stars quiz
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
When has a low mass star
reached its largest size?
Click on the right
region in HR
diagram!
Return to
Main Page
Next
question

33. Stellar evolution low mass stars quiz
When has a low mass star
reached its largest size?
Correct!
On the Asymptotic Giant Branch a low mass star has
reached its largest size of ~100 times larger than our Sun.
Next
question
Return to
Main Page

34. Stellar evolution low mass stars quiz
When has a low mass star
reached its largest size?
Wrong!
Either try again or
have another look at the size evolution slides
Redo
question
Return to
Main Page

35. Stellar evolution low mass stars quiz
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Which are the three longest
evolutionary stages
of a low mass star?
Click on the one of the
right regions in HR
diagram!
Previous
question
Next
question
Return to
Main Page

36. Stellar evolution low mass stars quiz
Which are the three longest evolutionary stages of a low mass star?
Correct!
The main sequence is the longest evolutionary phase of a
low mass star. Our Sun remains for 4.5billion years a main
sequence star.
Try to find the other phases or go to the next question.
Redo
question
Next
question
Return to
Main Page

37. Stellar evolution low mass stars quiz
Which are the three longest evolutionary stages of a low mass star?
Correct!
The horizontal branch is the third longest evolutionary
phase of a low mass star.
Try to find the other phases or go to the next question.
Redo
question
Next
question
Return to
Main Page

38. Stellar evolution low mass stars quiz
Which are the three longest evolutionary stages of a low mass star?
Correct!
The white dwarf phase is the second longest evolutionary
phase of a low mass star. Actually this isn't a real phase.
It is more the like the grave of a low mass star.
Try to find the other phases or go to the next question.
Redo
question
Return to
Main Page

39. Stellar evolution low mass stars quiz
Which are the three longest evolutionary stages of a low mass star?
Wrong!
Either try again or
have another look at the evolutionary speed slides.
Redo
question
Return to
Main Page

40. Stellar evolution low mass stars quiz
Which colour does a
giant in the evolution of a
low mass star have before it
becomes a planetary nebula?
Click on the
right colour!
Luminosity
Surface Temperature
main sequence
white dwarf K
2 500 K
1 Sun
Sun
0.001 Sun
Previous
question
Return to
Main Page

41. Stellar evolution low mass stars quiz
Which colour does a giant in the
evolution of a low mass star have before
it becomes a planetary nebula?
Correct!
These stars are very red since they are very cool.
Our Sun will become as cold as K on its surface.
Return to
Main Page

42. Stellar evolution low mass stars quiz
Which colour does a giant in the
evolution of a low mass star have before
it becomes a planetary nebula?
Wrong!
Either try again or
have another look at the colour change slides.
Redo
question
Return to
Main Page

43. Info on low mass evolution
Main
Page
Click on an evolutionary
phase in the HR diagram
you want to learn
more about!
Red Giants
Horizontal Branch
Planetary Nebula
Sun
Luminosity
1 Sun
0.001 Sun
White Dwarfs K
2 500 K
Surface Temperature

44. Red Giants Betelgeuse Mira Info Page NEXT
Red giants are sooo large that we can actually 'see' their size.
Sadly we have to use very special techniques and
can't just look through a very large telescope.
Many bright red stars we see in the sky are red giants.

45. Red Giants NGC 6888 - Crecent Nebula Previous Info Page NEXT
Red giants lose some of their mass during their evolution.
This material can form beautiful nebula around them and
also enriches the surrounding space with heavy elements.

46. An artists impression of a
Red Giants
Info
Page
An artists impression of a
Supernova Type Ia
The Red Giant on the right is in a double star system.
It provides material for a white dwarf on the left. If the white dwarf collects enough
material it will explode as a Supernova (Type Ia). Since this happens at a
very specific mass and the brightness depends on the mass, we can
use these special Supernova to derive distances to very distant galaxies.

47. A HR diagram of a cluster of old stars
Horizontal Branch
Info
Page
NEXT
A HR diagram of a cluster of old stars
In this figure it becomes clear why these stars are called horizontal stars:
The location of all horizontal branch stars is highlighted and they all
lie in a horizontal region.

48. Variable Horizontal branch stars
Previous
Info
Page
Variable Horizontal branch stars
You will have noticed that some horizontal branch stars seemed to be
above the normal region favoured by the others.
These special stars are variable stars. Maybe you can spot them in
the image of an old stellar cluster.
These special stars are used to determine distance in our Galaxy.

49. Planetary Nebula M57 - Ring nebula Info Page NEXT
During the Planetary Nebula phase the star becomes a white dwarf
and ejects all its mass into space. What remains is a white dwarf in the centre
and a beautiful symetric nebula. It looks like a ring since the mass the star
has lost is in a spherical shell around it.

50. Planetary Nebula NGC 6543 Previous Info Page NEXT
Sometimes the mass ejected by the star interacts with the mass it has
lost during the Red Giant Phase and creates more complicated patterns.
Here the nebula actually consists of two sperical shells.
one to the top left and one to the bottom right of the star.

51. Planetary Nebula Previous Info Page
In some cases the two spherical shells look as if they are open at each end.

52. White dwarfs in an old stellar cluster
Info
Page
NEXT
White dwarfs in an old stellar cluster
White dwarfs are difficulat to observe since they are the
faintest phase in the low mass stars evolution. However you will
end up with loads of them after a while in an old cluster.

53. An artists impression of a
White Dwarfs
Previous
Info
Page
An artists impression of a
Supernova Type Ia
The Red Giant on the right is in a double star system.
It provides material for a white dwarf on the left. If the white dwarf collects enough
material it will explode as a Supernova (Type Ia). Since this happens at a
very specific mass and the brightness depends on the mass, we can
use these special Supernova to derive distances to very distant galaxies.