Related papers: Luminosity versus Rotation in a Supermassive Star
Measured rotational speeds of giant planets and brown dwarfs frequently constitute appreciable fractions of the breakup limit, resulting in centrifugal expansion of these objects at the equator. According to models of internal energy…
We calculate a grid of models with and without the effects of axial rotation for massive stars in the range of 9 to 60 M$_{\odot}$ and metallicity $Z$ = 0.004 appropriate for the SMC. Remarkably, the ratios $\Omega/\Omega_{\mathrm{crit}}$…
In addition to being spectacular objects, Very Massive Stars (VMS) are suspected to have a tremendous impact on their environment and on the whole cosmic evolution. The nucleosynthesis both during their advanced stages and their final…
The evolution of massive stars even on the main sequence is not yet well understood. Due to the steep mass-luminosity relation, massive main sequence stars become very luminous. This brings their envelopes very close to the Eddington limit.…
Fast rotation of compact stars (at submillisecond period) and, in particular, their stability, are sensitive to the equation of state (EOS) of dense matter. Recent observations of XTE J1739-285 suggest that it contains a neutron star…
Be stars are thought to be fast rotating stars surrounded by an equatorial disc. The formation, structure and evolution of the disc are still not well understood. In the frame of single star models, it is expected that the surface of an…
Active solar-type stars show large quasi-periodic brightness variations caused by stellar rotations with star spots, and the amplitude changes as the spots emerge and decay. The Kepler data are suitable for investigations on the emergence…
The gravitational action of the smooth energy-matter components filling in the universe can affect the orbit of a planetary system. Changes are related to the acceleration of the cosmological scale size R. In a universe with significant…
Evolved stars dominate galactic spectra, enrich the galactic medium, expand to change their planetary systems, eject winds of a complex nature, produce spectacular nebulae and illuminate them, and transfer material between binary…
The amplitude and morphology of light curves of solar-like stars change substantially with increasing rotation rate: brightness variations get amplified and become more regular, which has so far not been explained. We develop a modelling…
Recent results from gravitational lensing are combined with new modeling of the stellar velocity distributions in nearby galaxies to probe the connection between the luminous and the dark matter in elliptical galaxies. From analysing a…
We perform 3D numerical simulations in full general relativity to study the stability of rapidly rotating, supramassive neutron stars at the mass-shedding limit to dynamical collapse. We adopt an adiabatic equation of state with $\Gamma =…
Some studies have claimed the existence of a stellar upper-mass limit of 150 Msun. A factor that is often overlooked concerns the issue that there might be a significant difference between the present-day and the initial mass of the most…
Precise photometry from the Kepler space telescope allows not only the measurement of rotation in solar-type field stars, but also the determination of reliable masses and ages from asteroseismology. These critical data have recently…
Stellar rotation significantly shapes the evolution of massive stars, yet the interplay of mass and metallicity remains elusive, limiting our capacity to construct accurate stellar evolution models and to better estimate the impact of…
We discuss the physics and the evolution of a typical massive star passing through an evolutionary stage similar to that of Betelgeuse. After a brief introduction recalling various observed parameters of Betelgeuse, we discuss the…
Rotational light modulation in Kepler photometry of K - A stars is used to estimate the absolute rotational shear. The rotation frequency spread in 2562 carefully selected stars with known rotation periods is measured using time-frequency…
Luminous blue variables are an intermediate stage in the evolution of high-mass stars characterized by extreme mass loss and substantial variability. The stars show large irregular episodic variations on timescales of years to decades in…
Context. Kepler-17 is a G2V sun-like star accompanied by a transiting planet with a mass of ~2.5 Jupiter masses and an orbital period of 1.486 d, recently discovered by the Kepler space telescope. This star is highly interesting as a young…
In seven billion years, the Sun will be dead. As stars like the Sun pass from their present state to that of a dead white dwarf star, they undergo two phases of extremely high luminosity and radius -- the red giant branch and the asymptotic…