Tolman-Oppenheimer-Volkoff border

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The Tolman-Oppenheimer-Volkoff limit ( TOV limit ) is an upper limit for the mass of neutron stars , analogous to the Chandrasekhar limit for white dwarfs .

The limit was calculated in 1939 by Robert Oppenheimer and George Michael Volkoff based on the work of Richard C. Tolman . They assumed that the neutrons of a neutron star are in the form of a cold, degenerate Fermi gas . This resulted in a limit mass of 0.71  solar masses (M ). Modern estimates range from 1.5 to 3.2 M . The uncertainty results from the fact that the equations of state for dense hadronic matter are not yet exactly known. In April 2013, John Antoniadis and colleagues announced that their investigations into the  binary star system PSR J0348 + 0432, which consists of a neutron star and a white dwarf, showed a neutron star mass of 2.01 ± 0.04 M .

Below the TOV limit, the weight of the neutron star is supported by short-range neutron-neutron interactions, which are mediated by the strong interaction and the degeneracy pressure of the neutrons. Above the border, the object collapses directly into a black hole .

However, some astrophysicists suspect that neutron stars above the TOV limit will collapse into a quark star if they are stabilized by the quark degeneracy pressure. The properties of this hypothetical degenerate quark matter are even less understood than those of the degenerate neutron matter.


  1. ^ Static Solutions of Einstein's Field Equations for Spheres of Fluid , Richard C. Tolman, Physical Review 55 , # 374 (February 15, 1939 ), pp. 364-373.
  2. On Massive Neutron Cores , JR Oppenheimer and GM Volkoff, Physical Review 55 , # 374 (February 15, 1939 ), pp. 374-381.
  3. Ignazio Bombaci: The maximum mass of a neutron star . In: Astronomy & Astrophysics . 305, 1996, pp. 871-877. bibcode : 1996A & A ... 305..871B .
  4. ^ John Antoniadis et al .: A Massive Pulsar in a Compact Relativistic Binary . In: Science . 340, 2013. doi : 10.1126 / science.1233232 .