相关论文: Testing Gravity Using Dwarf Stars

A large fraction of the observed brown dwarfs may form by gravitational fragmentation of unstable discs. This model reproduces the brown dwarf desert, and provides an explanation the existence of planetary-mass objects and for the binary…

For a rotating galaxy, the inner circular-velocity gradient d_{R}V(0) provides a direct estimate of the central dynamical mass density, including gas, stars, and dark matter. We consider 60 low-mass galaxies with high-quality HI and/or…

We report the results of a deep near infrared (JHK) survey of the outer parts of the Trapezium Cluster with Gemini South/Flamingos. 396 sources were detected in a 26 arcmin^2 area, including 138 brown dwarf candidates, defined as M<0.075…

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…

We rehearse the physical and theoretical considerations that define the nature of Brown Dwarfs, in particular the maximum mass for a Brown Dwarf (set by the Hydrogen-Burning Limit) and the minimum mass for a Brown Dwarf (set by the Opacity…

In this paper, we explore the prospect for improving the measurement accuracy of masses and radii of neutron stars. We consider imminent and long-term upgrades of the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo, as…

Some tests of gravity theories - periastron shift, geodetic precession, change in mean motion and gravitational redshift - are applied in solar and stellar systems to constrain the cosmological constant. We thus consider a length scale…

While QCD appears not to be accurately solvable in the regime of interest for neutron star physics, microscopic calculations are feasible at both low and very high densities. In this work, we propose using the most realistic calculations in…

Theories with varying gravitational constant $G$ have been studied since long time ago. Among them, the most promising candidates as alternatives of the standard General Relativity are known as scalar-tensor theories. They provide…

Properties of rotating neutron stars with the use of relativistic mean-field theory are considered. The performed analysis of neutron star matter is based on the nonlinear Lgrangian density. The presence of nonlinear interaction of vector…

Galaxy groups can be characterized by the radius of decoupling from cosmic expansion, the radius of the caustic of second turnaround, and the velocity dispersion of galaxies within this latter radius. These parameters can be a challenge to…

Assuming static and spherically symmetric stars with perfect fluid matter, we used realistic equations of state to study neutron stars in covariant $f(Q)$ gravity. The structure profiles and properties of neutron stars such as mass, radius…

The discovery of $19$ dwarf galaxies without dark matter provides, counter-intuitively, strong support for the $\Lambda$CDM standard model of cosmology. Their presence is well accommodated in a scenario where the dark matter is in the form…

Using a perturbative approach we solve stellar structure equations for low-density (solar-type) stars whose interior is described with a polytropic equation of state in scenarios involving a subset of modified gravity theories. Rather than…

During its active lifetime a star burns its nuclear fuel and gravitation is held off by the pressure of the heated gas. Gravity should take over once this fuel is exhausted unless some other agency saves the star from such a fate. Low mass…

In a series of articles we describe a novel class of geometrical models of relativistic stars. Our approach to the static spherically symmetric solutions of Einstein equations is based on a careful physical analysis of radial gauge…

We conducted a search for brown dwarf candidates in a James Webb Space Telescope deep field around A2744 to investigate the space density of these objects at kiloparsec distances. Our methodology employed an initial selection based on…

In this work we present a stellar structure model from $f(\mathcal{R})$-gravity point of view capable to describe some classes of stars (White Dwarfs, Brown Dwarfs, Neutron stars, Red Giants and the Sun). This model was based on…

Interacting white dwarf binary star systems, including helium cataclysmic variable (HeCV) systems, are expected to be strong sources of gravitational radiation, and should be detectable by proposed space-based laser interferometer…

Three observational tests of cosmological natural selection, a theory that follows from some hypotheses about quantum gravity, are described. If true, this theory explains the choices of the parameters of the standard model of particle…