相关论文: Models of stars rotating near the critical limit

The understanding of the evolution of early-type stars is tightly related to that of the effects of rapid rotation. For massive stars, rapid rotation combines with their strong radiation-driven wind. The aim of this paper is to investigate…

Whenever stars are rotating very fast (Omega/Omega_crit > 0.7, with Omega_crit the Keplerian angular velocity of the star accounting for its deformation) radiative stellar winds are enhanced in polar regions. This theoretical prediction is…

We argue that, in general, observational studies of Be-star rotation have paid insufficient attention to the effects of equatorial gravity darkening. We present new line-profile calculations that emphasize the insensitivity of line width to…

We determine which are the mechanisms accelerating the surface of single stars during the Main Sequence evolution. We have computed 112 stellar models of four different initial masses between 3 and 60 M_sun, at four different metallicities…

Several properties of massive stars with large effects of rotation and radiation are studied. We show that there are 2 roots for the equation giving the rotational velocities at break-up: 1) The usual solution, which is shown to apply when…

Continuum driving is an effective method to drive a strong stellar wind. It is governed by two limits: the Eddington limit and the photon-tiring limit. A star must exceed the effective Eddington limit for continuum driving to overcome the…

The theory of radiation driven wind including stellar rotation is re-examined. After a suitable change of variables, a new equation for the mass loss rate is derived analytically. The solution of this equation remains within 1% confidence…

The understanding of the rotational evolution of early-type stars is deeply related to that of anisotropic mass and angular momentum loss. In this paper, we aim to clarify the rotational evolution of rapidly rotating early-type stars along…

The travel times of light signals between two antipodal points on the surface of a compact star are calculated for two different trajectories: a straight line that passes through the center of the star and a semi-circular trajectory that…

We summarize the present status of the predictions of massive star models for the evolution of their surface properties. After discussing luminosity, temperature and chemical composition, we focus on the question whether massive stars may…

We study the dynamics of continuum driven winds from rotating stars, and develop an approximate analytical model. We then discuss the evolution of stellar angular momentum, and show that just above the Eddington limit, the winds are…

Massive stars may during their evolution reach the phase of critical rotation when the further increase in rotational speed is no longer possible. The ejection of matter in the equatorial region forms the gaseous outflowing disk, which…

Many stars -- if they could be imaged with enough angular resolution -- would exhibit features expected from theory but not possible to extract from spectra. We may group these by increasing complexity as follows. First, smooth variations…

As a planet transits the face of a star, it accelerates along the line-of-sight. The changing delay in the propagation of photons produces an apparent deceleration of the planet across the sky throughout the transit. This persistent…

We have incorporated the oblate distortion of the shape of the star due to the stellar rotation, which modifies the finite disk correction factor (f_D) in the m-CAK hydrodynamical model. We implement a simplified version for the f_D…

Mass loss is a determinant factor which strongly affects the evolution and the fate of massive stars. At low metallicity, stars are supposed to rotate faster than at the solar one. This favors the existence of stars near the critical…

The envelopes of stars near the Eddington limit are prone to various instabilities. A high Eddington factor in connection with the Fe opacity peak leads to convective instability, and a corresponding envelope inflation may induce…

We show that the luminosity of a star forming galaxy is capped by the production and subsequent expulsion of cosmic rays from its interstellar medium. By defining an Eddington luminosity in cosmic rays, we show that the star formation rate…

Fast rotation seems to be the major factor to trigger the Be phenomenon. Surface fast rotation can be favored by initial formation conditions such as metal abundance. Models of fast rotating atmospheres and evolutionary tracks are used to…

Angular momentum is a key property regulating star formation and evolution. However, the physics driving the distribution of the stellar rotation rates of early-type main-sequence stars is as yet poorly understood. Using our catalog of…