Week 4    go to         https://uofgts.com/Astro/week4.html

Stars How Do We Know what they are?

The Electromagnetic Spectrum

• radiation
• Cosmic Rays

• Visible Light
• Solar Spectrum
• Stellar Spectrum

Classification of Stars

• Spectral Type
• Luminosity

The HR Diagram

• Absolute Magnitude or Luminosity Vs Spectral Type/Temperature/Color

Evolution of a 1 solar mass star (Sun)

• Nebula
• T-Tauri
• Main Sequence
  
• Red Giant
  
• Nova
  
• White Dwarf (C-N-O)
  

Evolution of a 5 - 8 solar mass star

• Carbon Star explodes (fusion stops at C-N-O)
  
• No remnant
  

Evolution of a 8 - 80 solar mass star (Super Giant)

• Shell detonation
  
• blows off envelope
  
• leaves collapsed core
  
• Either a neutron star, or a Black Hole
  
• Fe Fusion adsorbs energy
  
• The Star collapses
  
• Super Novas
• Some heavy elements beyond Fe (Iron) Form during the Super Nova
  

End Points

• White Dwarfs
• Neutron Stars
• Black Holes

Celestial Sign Posts in the Summer Sky

8 - 12 pm, in August