Related papers: Stars creating a gravitational repulsion
The cosmological constant problem represents an evident tension between our present description of gravity and particle physics. Many solutions have been proposed, but experimental tests are always difficult or impossible to perform and…
We introduce a toy model that describes (in a single equation) the mass in stars as a function of halo mass and redshift. Our model includes the suppression of gas accretion from gravitational shock heating and AGN jets mainly for M_halo >…
Runaway stellar collisions in dense star clusters are invoked to explain the presence of very massive stars or blue stragglers in the center of those systems. This process has also been explored for the first star clusters in the Universe…
Compression of the stellar winds from rapidly rotating hot stars is described by the wind compression model. However, it was also shown that rapid rotation leads to rotational distortion of the stellar surface, resulting in the appearance…
Non-rotating neutron stars are generally treated in theoretical studies as perfect spheres. Such a treatment, however, may not be correct if strong magnetic fields are present (such as for magnetars) and/or the pressure of the matter in the…
Scalar-tensor~(ST) theories of gravity are natural phenomenological extensions to general relativity. Although these theories are severely constrained both by solar system experiments and by binary pulsar observations, a large set of ST…
We propose a simple analytic model to understand when star formation is time-steady versus bursty in galaxies. Recent models explain the observed Kennicutt-Schmidt relation between star formation rate and gas surface densities in galaxies…
The gravitational radiation from compact pulsar-like stars depends on the state of dense matter at supranuclear densities, i.e., the nature of pulsar (e.g., either normal neutron stars or quark stars). The solid quark star model is focused…
Axion stars, gravitationally bound states of low-energy axion particles, have a maximum mass allowed by gravitational stability. Weakly bound states obtaining this maximum mass have sufficiently large radii such that they are dilute, and as…
This paper reviews the physics of stars, the type, structure, evolution and stability. Simple thermodynamics and statistical mechanics are used to show the inner working of white dwarf and neutron stars. The major concentration of the paper…
The existence of stars with a large mass of 2 solar masses means that the equation of state is stiff enough to provide high enough pressure at large central densities. Previous work shows that such a stiff equation of state is possible if…
A variety of stellar explosions powered by black hole accretion are discussed. All involve the failure of neutrino energy deposition to launch a strong supernova explosion. A key quantity which determines the type of high energy transient…
Neutron stars are some of the densest manifestations of massive objects in the universe. They are ideal astrophysical laboratories for testing theories of dense matter physics and provide connections among nuclear physics, particle physics…
Gravitational waves are tiny disturbances in space-time and are a fundamental, although not yet directly confirmed, prediction of General Relativity. Rapidly rotating neutron stars are one of the possible sources of gravitational radiation…
Massive stars (with mass m_* > 8 solar masses) are fundamental to the evolution of galaxies, because they produce heavy elements, inject energy into the interstellar medium, and possibly regulate the star formation rate. The individual star…
Spherically symmetric configurations of the non-interacting massive complex scalar field, representing non-rotating boson stars, are considered within the framework of the modified torsion based $f(T)$ gravity, with $f(T) = T + \alpha \,…
A simple general relativity theory for objects moving in gravitational fields is developed based on studying the behavior of an atom in a gravitational field. The theory is applied to calculate the satellite time dilation, light deflection…
In this paper we study the phenomenology of stars and galaxies in massive bigravity. We give parameter conditions for the existence of viable star solutions when the radius of the star is much smaller than the Compton wavelength of the…
Gravity and thermal energy are universal phenomena which compete over the stabilization of astrophysical systems. The former induces an inward pressure driving collapse and the latter a stabilizing outward pressure generated by random…
A star of mass greater than a critical mass is believed to undergo gravitational collapse to form a singularity, owing to Hawking-Penrose singularity theorem which is based on the Raychaudhuri equation in the absence of torsion. We argue…