SWS Central Program--- Stars (110 hr; 25%)

• Gas/dust debris disks around YSO's
  (Wesselius; Waelkens).
  • Are all young stars surrounded by dusty disks?
  • How does gas & dust evolve as stars approach main sequence?
  • What termines time-scale for dispersal of material?
  • How do massive disks evolve into low-mass Beta Pic discs?
  • Is planet formation common or exceptional in such disks?
• MS & Post-MS evolution of massive OB stars
  (Waters; Lamers; van der Hutch).
  • Mass loss drives evolution: Wolf-Rayet vs. red supergiant, etc.
  • Mass outflows studied via HI, HeI, HeII recombination lines, forbidden lines, and free-free continuum.
  • Mass loss mechanism, mass loss rate, abundances.
• Post-MS evolution of low & intermediate mass stars
  (de Jong; Waters; Beintema).
  • Evolution on AGB and beyond is driven by slow, dusty winds.
  • The mass loss rate exceeds nuclear burning rate by as much as 10X.
  • Determine AGB mass loss dependence on mass, lum. and composition.
  • No reliable theory for AGB mass loss yet exists.

• SWS Scientific Capabilities (Back)