Compact Stellar Objects

Remnant cores of massive stars following nuclear fuel exhaustion, characterized by extreme density and support via degeneracy pressure or gravitational collapse. Classification governed by progenitor mass and equation of state.

Classification

  • White Dwarf: Electron degeneracy pressure; Chandrasekhar limit ~1.4 M☉; endpoints of low-to-intermediate mass stars.
  • Neutron Star: Neutron degeneracy pressure; Tolman-Oppenheimer-Volkoff limit; subtypes include Pulsar and Magnetar.
  • Stellar Black Hole: Gravitational collapse exceeding TOV limit; event horizon; no quantum pressure resistance.
  • Exotic candidates: Quark stars, boson stars, gravastars (theoretical).

Formation & Evolution

  • Endpoints of stellar-evolution determined by initial mass, metallicity, and rotation.
  • Supernova mechanisms: Core-collapse (Type II/Ib/Ic), Thermonuclear (Type Ia via White Dwarf accretion/merger).
  • Binary dynamics: Accretion-induced collapse, common envelope evolution, compact binary mergers (NS-NS Merger, NS-BH Merger).

Galactic Center & Sgr A* Phenomena