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Related papers: Mass fluxes for O stars

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Context. Traditionally, supersonic turbulence is considered to be one of the most likely mechanisms to slow down the gravitational collapse in dense clumps, thereby enabling the formation of massive stars. However, several recent studies…

Monte Carlo techniques are used to model nonlinear particle acceleration in parallel collisionless shocks of various speeds, including mildly relativistic ones. When the acceleration is efficient, the backreaction of accelerated particles…

Astrophysics · Physics 2016-08-30 Donald C. Ellison , Glen P. Double

We used Fourier transform techniques to determine macroturbulent velocity. The analysis is done with mictoturbulent velocity and rotation velocity as an unknown quantities. In order to distinguish the effects of rotation from…

Solar and Stellar Astrophysics · Physics 2020-04-08 V. A. Sheminova

Spectral lines of hot massive stars are known to exhibit large excess broadening in addition to rotational broadening. This excess broadening is often attributed to macroturbulence whose physical origin is a matter of active debate in the…

Solar and Stellar Astrophysics · Physics 2024-12-18 Nadya Serebriakova , Andrew Tkachenko , Conny Aerts

We simulate a self-gravitating, turbulent cloud of 1000 Msol with photoionization and radiation pressure feedback from a 34 Msol star. We use a detailed Monte Carlo radiative transfer scheme alongside the hydrodynamics to compute…

Astrophysics of Galaxies · Physics 2018-04-23 Ahmad Ali , Tim J. Harries , Thomas A. Douglas

The acceleration of energetic particle transport in high amplitude magnetosonic and Alfvenic turbulence is considered using the method of Monte Carlo particle simulations, involving integration of particle equations of motion. We derive the…

Astrophysics · Physics 2009-09-25 G. Michalek , M. Ostrowski , R. Schlickeiser

Convection and turbulence in stellar atmospheres have a significant effect on the emergent flux from late-type stars. The theoretical advancements in convection modelling over recent years have proved challenging for the observers to obtain…

Astrophysics · Physics 2015-06-24 Barry Smalley

The motion of atoms and nanoparticles in a trap formed by sequences of counter-propagating light pulses has been analyzed. The atomic state is described by a wave function constructed with the use of the Monte Carlo method, whereas the…

Atomic Physics · Physics 2013-05-23 V. I. Romanenko , A. V. Romanenko , Ye. G. Udovitskaya , L. P. Yatsenko

Line-driven winds from hot stars and accretion disks are thought to adopt a unique, critical solution which corresponds to maximum mass loss rate and a particular velocity law. We show that in the presence of negative velocity gradients,…

Astrophysics · Physics 2009-10-31 Achim Feldmeier , Isaac Shlosman

Mass-loss rate is one of the most important stellar parameters. We aim to provide mass-loss rates as a function of subdwarf parameters and to apply the formula for individual subdwarfs, to predict the wind terminal velocities, to estimate…

Solar and Stellar Astrophysics · Physics 2016-10-05 J. Krticka , J. Kubat , I. Krtickova

Mass loss through stellar winds plays a dominant role in the evolution of massive stars. In particular the mass-loss rates of very massive stars (VMSs, $> 100\,M_{\odot}$) are highly uncertain. Such stars display Wolf-Rayet spectral…

Solar and Stellar Astrophysics · Physics 2020-02-26 Joachim M. Bestenlehner

We investigate the ionization of the diffuse interstellar medium by cosmic rays by modeling their propagation along the wandering magnetic fields using a Monte Carlo method. We study how low-energy cosmic rays propagate in turbulent,…

High Energy Astrophysical Phenomena · Physics 2022-12-05 Riccardo Franceschi , Steven Neil Shore

Star formation is intimately linked to the dynamical evolution of molecular clouds. Turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass via accretion from the surrounding cloud…

Astrophysics · Physics 2007-05-23 Ralf Klessen

We present two self-consistent procedures that couple the hydrodynamics with calculations of the line-force in the frame of radiation wind theory. These procedures give us the line-force parameters, the velocity field, and the mass-loss…

Solar and Stellar Astrophysics · Physics 2020-02-19 Alex Camilo Gormaz-Matamala

Context. Radiation-driven mass loss is key to our understanding of massive-star evolution. However, for low-luminosity O-type stars there are big discrepancies between theoretically predicted and empirically derived mass-loss rates (called…

Solar and Stellar Astrophysics · Physics 2021-04-21 C. Lagae , F. A. Driessen , L. Hennicker , N. D. Kee , J. O. Sundqvist

One of the defining processes which govern massive star evolution is their continuous mass loss via dense, supersonic line-driven winds. In the case of those OB stars which also host a surface magnetic field, the interaction between that…

Solar and Stellar Astrophysics · Physics 2018-01-25 A. David-Uraz , V. Petit , C. Erba , A. Fullerton , N. Walborn , R. MacInnis

Because of their activity, late-type stars are known to host powerful flares producing intense high-energy radiation on short time-scales that may significantly affect the atmosphere of nearby planets. We employ a one-dimensional aeronomic…

Earth and Planetary Astrophysics · Physics 2018-12-26 D. V. Bisikalo , V. I. Shematovich , A. A. Cherenkov , L. Fossati , C. Moestl

Thermonuclear burning on the surface of a neutron star causes the expansion of a thin outer layer of the star, $\Delta R(t)$. The layer rotates slower than the star due to angular momentum conservation. The shear between the star and the…

Astrophysics · Physics 2008-11-26 Richard V. E. Lovelace , Akshay K. Kulkarni , Marina M. Romanova

We have determined accurate values of the product of the mass-loss rate and the ion fraction of P^{4+}, Mdot q(P^{4+}), for a sample of 40 Galactic O-type stars by fitting stellar-wind profiles to observations of the P V resonance doublet…

Astrophysics · Physics 2008-11-26 A. W. Fullerton , D. L. Massa , R. K. Prinja

A new set of laws of motion for turbulent jets propagating in an intergalactic medium characterized by a decreasing density is derived by applying conservation of momentum flux both in the classical and relativistic framework. Two…

High Energy Astrophysical Phenomena · Physics 2015-08-04 L. Zaninetti