Comparison of theoretical radiation-driven winds from stars and discs
نویسنده
چکیده
We compare models of line-driven winds from accretion discs and single spherical stars. We look at the problem of scaling mass-loss rates and velocities of stellar and disc winds with model parameters. We find that stellar and disc winds driven by radiation, within the CAK framework, are very similar as far as mass-loss rates and velocities are concerned. Thus we can use analytic results for stellar winds to rescale, in a first order approximation, numerical results for disc winds. We also show how the CAK stellar solutions change when we take into account effects of very low luminosities or line-driving force.
منابع مشابه
On the mass - loss of PG 1159 stars ?
The winds of the four PG 1159 stars NGC7094, NGC246, K 1-16 and RX J2117.1+3412 are investigated by means of non-LTE models for spherically expanding atmospheres. Based on the results of recent plane-parallel non-LTE analyses, several individual models with variousmass-loss rates are calculated. Synthetic profiles of the C iv resonance line are compared to high resolution, high quality HST and ...
متن کاملLine-driven ablation of circumstellar discs – I. Optically thin decretion discs of classical Oe/Be stars
The extreme luminosities of massive, hot OB stars drive strong stellar winds through line-scattering of the star's UV continuum radiation. For OB stars with an orbiting circumstellar disc, we explore here the effect of such line-scattering in driving an ablation of material from the disc's surface layers, with initial focus on the marginally optically thin decretion discs of classical Oe and Be...
متن کاملThe effects of X-ray photoionization and heating on the structure of circumstellar discs
We present the results of a theoretical study investigating the effects of photoionization and heating by X-rays on discs around low-mass stars. In particular we address the question of whether or not X-rays can drive a disc wind. First, we construct a 1-dimensional “quasi-hydrostatic” model, which solves for the vertical structure introduced by X-ray heating. We consider uniform X-ray illumina...
متن کاملRadiation driven atmospheres of O-type stars: constraints on the mass–luminosity relation of central stars of planetary nebulae
Recent advances in the modelling of stellar winds driven by radiation pressure make it possible to fit many wind-sensitive features in the UV spectra of hot stars, opening the way for a hydrodynamically consistent determination of stellar radii, masses, and luminosities from the UV spectrum alone. It is thus no longer necessary to assume a theoretical mass–luminosity relation. As the method has...
متن کاملAn explanation for the curious mass loss history of massive stars: from OB stars, through Luminous Blue Variables to Wolf-Rayet stars
The stellar winds of massive stars show large changes in mass-loss rates and terminal velocities during their evolution from O-star through the Luminous Blue Variable phase to the Wolf-Rayet phase. The luminosity remains approximately unchanged during these phases. These large changes in wind properties are explained in the context of the radiation driven wind theory, of which we consider four ...
متن کامل