相关论文: Tachyon stars
In General Relativity there is a maximum mass allowed for neutron stars that, if exceeded, entails their collapse into a black hole. Its precise value depends on details of the nuclear matter equation of state about which we are much more…
Gravitational instability is one of considerable mechanisms to explain the formation of giant planets. We study the gravitational stability for the protoplanetary disks around a protostar. The temperature and Toomre's Q-value are calculated…
It is suggested that charged tachyons of extremely large mass M could not only contribute to the dark matter needed to fit astrophysical observations, but could also provide an explanation for gamma ray bursts and ultra high energy cosmic…
Motivated by the recent "Cosmos Project" observation of dark-matter concentrations with no ordinary matter in the same place, we study the question of the existence of compact objects made of pure dark matter. We assume that the dark matter…
In cold dark matter cosmology, the baryonic components of galaxies are thought to be mixed with and embedded in non-baryonic and non-relativistic dark matter, which dominates the total mass of the galaxy and its dark matter halo. In the…
One of the most intringuing questions about neutron stars concerns their maximum mass. The answer is intimately related to the properties of matter at densities far beyond that found in heavy atomic nuclei. The current view on the internal…
We present a detailed study of cosmological effects of homogeneous tachyon matter coexisting with non-relativistic matter and radiation, concentrating on the inverse square potential and the exponential potential for the tachyonic scalar…
While the total interior mass of a galaxy is reasonably well determined by a good rotation curve, the relative contributions from disk, bulge and halo are only weakly constrained by one-dimensional data. Barred galaxies are intrinsically…
A static, spherically symmetric spacetime with negative pressures is conjectured inside a star. The gravitational field is repulsive and so a central singularity is avoided. The positive energy density and the pressures of the imperfect…
The relativistic equations of hydrostatic equilibrium for a spherically symmetric star, or the Tolman-Oppenheimer-Volkoff equations are known in higher dimensions. In this paper, these equations have been expressed in terms of parameters of…
We obtain a mass function solving the Tolman-Oppenheimer-Volkoff (TOV) equation for isotropic and spherically symmetric system via homotopy perturbation method (HPM). Using the mass function we construct a stellar model which can be…
The anomalous orbits of Trans-Neptunian Objects (TNOs) can be explained by the Planet 9 hypothesis. We propose that the Planet 9 can be an axion star. Axion stars are gravitational bound clusters condensed by QCD axions or axion-like…
We investigate the properties of the static neutron stars and strangeness-mixed stars, based on the equations of state derived from a pion mean-field approach. Using the empirical data on the pion-nucleus scattering and bulk properties of…
The collapse of massive molecular clumps can produce high mass stars, but the evolution is not simply a scaled-up version of low mass star formation. Outflows and radiative effects strongly hinder the formation of massive stars via…
Star formation depends on the available gaseous "fuel" as well as galactic environment, with higher specific star formation rates where gas is predominantly molecular and where stellar (and dark matter) densities are higher. The partition…
We study the cosmological evolution of a tachyon scalar field T with a Dirac-Born-Infeld type lagrangian and potential V(T) coupled to a canonically normalized scalar field \phi with an arbitrary interaction term B(T,\phi) in the presence…
We wish to understand the processes that control the fluid flows of a gravitationally contracting and rotating star or giant planet. We consider a spherical shell containing an incompressible fluid that is slowly absorbed by the core so as…
Tensor-multi-scalar theories (TMST) are among the most natural generalizations of Einstein's theory, they are mathematically self-consistent and free from pathologies. They pass through all the known observations but contrary to standard…
We consider a gravitating spherically symmetric configuration consisting of a scalar field non-minimally coupled to ordinary matter in the form of a perfect fluid. For this system we find static, regular, asymptotically flat solutions for…
The properties of compact stars made of massive bosons with a repulsive selfinteraction mediated by vector mesons are studied within the mean-field approximation and general relativity. We demonstrate that there exists a scaling property…