Glossary
White Dwarfs

White Dwarfs
  • Ultimate fate for most of the Main Sequence stars in the galactic disk.
  • Form in low to intermediate mass stars ( <9 Msun )
    • in the centers of Red Giants
    • "revealed" when the upper layers of the Red Giant is ejected as a Planetary Nebula
  • Supported by electron degeneracy pressure
    • The result of the Pauli Exclusion Principle
    • Mass similar to Sun, Size similar to Earth
  • Not "burning" - just slowly emitting residual "heat"
    • Surface Temperatures < 1.2x104 K

The Binary system Sirius A,B, Sirius B (arrowed) is a White Dwarf
[Image Credit :Imagine the Universe ! and Lick Observatory]

Links

Additional Notes

White Dwarf Sub-classes (D is for dwarf):
  • DA White Dwarfs (most common) - display pressure-broadened hydgrogen absorption lines
  • DB White Dwarfs (least common) - display only He absorption lines
  • DC White Dwarfs - no features (pure continuum)