Related papers: Sources of Stellar Energy, Einstein- Eddington Tim…
Even when we consider Newtonian stars, i.e., stars with surface gravitational redshift, z<< 1, it is well known that, theoretically, it is possible to have stars, supported against self-gravity, almost entirely by radiation pressure.…
During the years from 1917 to 1921, A.S. Eddington was intensely occupied with Einstein's general theory of relativity and the epic eclipse expedition which confirmed one of the theory's predictions. During the same period, he investigated…
Supermassive stars (SMS) are massive hydrogen objects, slowly radiating their gravitational binding energy. Such hypothetical primordial objects may have been the seed of the massive black holes (BHs) observed at the centre of galaxies.…
Supermassive black holes are now realized to exist in the centers of most galaxies. The recent discoveries of luminous quasars at redshifts higher than 6 require that these black holes were assembled already when the Universe was less than…
In this letter we compute stringent astrophysical and cosmological constraints on a recently proposed Eddington-inspired Born-Infeld theory of gravity. We find, using a generalized version of the Zel'dovich approximation, that in this…
By using virial theorem, Helmholtz and Kelvin showed that the contraction of a bound self-gravitating system must be accompanied by release of radiation energy irrespective of the details of the contraction process. This happens because the…
In 1919 Einstein tried to solve the problem of the structure of matter by assuming that the elementary particles are held together solely by gravitational forces. In addition, Einstein also assumed the presence inside matter of…
I show that after the "helium flash" abruptly ends its first ascent red giant evolution, a solar-type star is powered primarily by gravitational contraction of its helium core, rather than by nuclear fusion. Because this energy is released…
The cosmological constant, which was introduced by Einstein a century ago to allow for a static universe, experienced a revival two decades ago under the label dark energy as a parameter to model the observed accelerated expansion of the…
Observations show that the expansion of the Universe is accelerating. This requires that the dominant constituent of matter in the Universe has some unusual properties like negative pressure. This exotic component has been given the name…
Eruptive mass loss in massive stars is known to occur, but the mechanism(s) are not yet well-understood. One proposed physical explanation appeals to opacity-driven super-Eddington luminosities in stellar envelopes. Here, we present a 1D…
We show that the disruption of a star by a 10^6 solar mass black hole in a galactic nucleus could under favorable circumstances produce an optically-thick envelope that radiates with a thermal spectrum at the Eddington limit, 10^{44} erg/s,…
The proximity to the Eddington luminosity has been attributed as the cause of several observed effects in massive stars. Computationally, if the luminosity carried through radiation exceeds the local Eddington luminosity in the low-density…
Hoyle and Folwler showed that there could be Radiation Pressure Supported Stars (RPSS) even in Newtonian gravity. Much later, Mitra found that one could also conceive of their General Relativistic (GR) version, "Relativistic Radiation…
Context: An impulsive increase in luminosity by one half or more of the Eddington value will lead to ejection of all optically thin plasma from Keplerian orbits around the radiating star, if gravity is Newtonian and the Poynting-Robertson…
We resurrect Eddington's proposal for the gravitational action in the presence of a cosmological constant and extend it to include matter fields. We show that the Newton-Poisson equation is modified in the presence of sources and that…
Black holes are assumed to decay via Hawking radiation. Recently we found evidence that spacetime curvature alone without the need for an event horizon leads to black hole evaporation. Here we investigate the evaporation rate and decay time…
A new covariant generalization of Einstein's general relativity is developed which allows the existence of a term proportional to $T_{\alpha\beta}T^{\alpha\beta}$ in the action functional of the theory ($T_{\alpha\beta}$ is the…
We study static spherically symmetric solutions to Einstein's equations with a repulsive singularity at the centre. We show that geodesics are extendible across the singularity, so the singularity does not lead to pathological causality…
Radiation pressure from the absorption and scattering of starlight by dust grains may be an important feedback mechanism in regulating star-forming galaxies. We compile data from the literature on star clusters, star-forming subregions,…