Download Mid Review of Section 2

Stellar Evolution up ‘til Now
The H-R Diagram
Stellar Evolution
• Main Sequence (core H fusion)
Stellar Evolution
• Main Sequence (core H fusion)
• Red Giant (core contraction,
Hydrogen shell burning)
Stellar Evolution
• Main Sequence (core H fusion)
• Red Giant (core contraction,
Hydrogen shell burning)
• Core Helium burning
Stellar Evolution
• Main Sequence (core H fusion)
• Red Giant (core contraction,
Hydrogen shell burning)
• Core Helium burning
• 2nd Giant Branch (core
contraction, H, He shell burning)
Mass Loss Occurs Here
Stellar Evolution
• Main Sequence (core H fusion)
• Red Giant (core contraction,
Hydrogen shell burning)
• Core Helium burning
• 2nd Giant Branch (core
contraction, H, He shell burning)
Mass Loss Occurs Here
If Core is Less Than 1.4 M
• Planetary Nebula (ionization of
mass lost by star)
• White Dwarf (inert C/O core)
Planetary Nebulae
Stellar Evolution
If Core is Greater Than 1.4 M
• Series of core burning and core
contractions
 Carbon to Magnesium, etc.
 Magnesium, etc., to Silicon, etc.
 Silicon, etc. to iron
• SUPERNOVA
Supernova Remnants
Elemental Synthesis
In the supernova explosion,
all the elements are made,
and are ejected into space
Stellar Endpoints
• If Remnant Core is less than 3 M
 Remnant is a Neutron Star
 If Magnetic Pole Points at Earth
 Remnant is a Pulsar
Stellar Endpoints
• If Remnant Core is less than 3 M
 Remnant is a Neutron Star
 If Magnetic Pole Points at Earth
 Remnant is a Pulsar
• If Remnant Core is greater than 3 M
 Remnant is a Black Hole
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The HR Diagram