## Abstract

The ratio of total mass m∗ to the surface radius r _{∗} of a spherical perfect fluid ball has an upper bound, Gm_{∗} (c^{2}r_{∗}) ≤B. Buchdahl (1959 Phys. Rev. 116 1027) obtained the value B_{Buch} = 4 9 under the assumptions that the object has a nonincreasing mass density in the outward direction and a barotropic equation of state. Barraco and Hamity (2002 Phys. Rev. D 65 124028) decreased Buchdahls bound to a lower value, B_{BaHa} = 3/8 (<4/9), by adding the dominant energy condition to Buchdahls assumptions. In this paper, we further decrease Barraco-Hamitys bound to B_{new} ≃ 0.3636403 (<3/8) by adding the subluminal (slower than light) condition of sound speed. In our analysis we numerically solve the Tolman-Oppenheimer-Volkoff equations, and the mass-to-radius ratio is maximized by variation of mass, radius and pressure inside the fluid ball as functions of mass density.

Original language | English |
---|---|

Article number | 215028 |

Journal | Classical and Quantum Gravity |

Volume | 32 |

Issue number | 21 |

DOIs | |

Publication status | Published - Oct 15 2015 |

Externally published | Yes |

## All Science Journal Classification (ASJC) codes

- Physics and Astronomy (miscellaneous)