Scattering

• coherent isotropic scattering
• awesome example: light echo
  • variable star V838 Mon image, movie
  • light echo from SN 1987A
  • Circinus X-1
  • Cas A
• random walks
• scattering and absorption: albedo
• stellar photospheres
  • themultiwavelength Sun today
  • Betelgeuse resolved: HST optical, IR, ALMA submm image, paper
  • circumstellar dus scattering in the Pleiades: relfection nebula

Radiative Flux in Stars: Rosseland Approximation

• energy flux
• Rosseland mean
• stellar interiors: radiative flux and local luminosity

Classical Electromagnetic Radiation

Fundamental Relations

• electromagnetic forces
• Maxwell's equations
• wavelike solutions; sketch