Star Formation

• fuel for star formation
• molecular clouds observed:
  • all-sky (CO data)
  • Barnard 68 (optical and IR)
  • Orion, nebula: HST optical and zoom, IR
• Jeans criterial for gravitational instability
• cloud fracmentation and protostars
• M16: Eagle nebula and HST zoom to pillars of creation
• protostars on the H-R diagram: the Hayashi way

The Main Sequence Across Stellar Masses

• trends summarized
• importance of helium core and thus stellar mixing

Convection in Stars

• convective instability
• example: granulation in the Sun
• condition for convection: temperature gradient