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Many stars across all classes possess strong enough magnetic fields to influence dynamical flow of material off the stellar surface. For the case of massive stars (O and B types), about 10\% of them harbour strong, globally ordered (mostly…

太阳与恒星天体物理 · 物理学 2023-04-05 Asif ud-Doula , Stan Owocki

Recent data support the idea that the filaments observed in H_alpha emission near the centres of some galaxy clusters were shaped by bulk flows within their intracluster media. We present numerical simulations of evaporated clump material…

天体物理学 · 物理学 2009-11-13 Edward Pope , Julian Pittard , Thomas Hartquist , Sam Falle

Fine-structure mid-infrared emission lines with critical densities in the regime 10^4 to 10^6 cm^-3 can be employed to probe the outflow from Wolf-Rayet stars at radii of \sim 10^15 cm. Narrow-band mid-infrared imaging and spectroscopy of…

太阳与恒星天体物理 · 物理学 2015-06-11 P. F. Roche , M. D. Colling , M. J. Barlow

(Abridged) The behaviour of mass loss across bi-stability jump is a key uncertainty in models of massive stars. While an increase in mass loss is theoretically predicted, this has so far not been observationally confirmed. However,…

太阳与恒星天体物理 · 物理学 2019-11-20 F. A. Driessen , J. O. Sundqvist , N. D. Kee

(Abridged) We consider the interaction of a relativistically-moving shell, composed of thermal photons, a reversing magnetic field and a small admixture of charged particles, with a dense Wolf-Rayet wind. A thin outer layer of Wolf-Rayet…

天体物理学 · 物理学 2008-11-26 Christopher Thompson

We analyze recent 2D simulations of the nonlinear evolution of the line-deshadowing instability (LDI) in hot-star winds, to quantify how the associated highly clumped density structure can lead to a "turbulent porosity" reduction in…

太阳与恒星天体物理 · 物理学 2018-01-31 Stanley P. Owocki , Jon O. Sundqvist

Protostellar outflows have been shown theoretically to be capable of maintaining supersonic turbulence in cluster-forming clumps and keeping the star formation rate per free-fall time as low as a few percent. We aim to test two basic…

太阳与恒星天体物理 · 物理学 2014-03-05 Fumitaka Nakamura , Zhi-Yun Li

We develop a kinetic theory for twisted density waves (phonons), carrying a finite amount of orbital angular momentum, in large magneto optical traps, where the collective processes due to the exchange of scattered photons are considered.…

量子气体 · 物理学 2016-02-17 J. D. Rodrigues , H. Terças , J. T. Mendonça

ALMA surveys have suggested that the dust in Class II disks may not be enough to explain the averaged solid mass in exoplanets, under the assumption that the mm disk continuum emission is optically thin. This optically thin assumption seems…

In order to understand the physical processes underlying clump formation in outflow from supercritical accretion flow, we performed two-dimensional radiation hydrodynamic (RHD) simulations. We focus our discussion on the nature of RHD…

高能天体物理现象 · 物理学 2015-06-18 S. Takeuchi , K. Ohsuga , S. Mineshige

Results of a study of the theoretically predicted and observed X-ray properties of local massive star clusters are presented, with a focus on understanding the mass and energy flow from these clusters into the ISM via a cluster wind. A…

天体物理学 · 物理学 2009-11-07 Ian R. Stevens , Joanna M. Hartwell

A small fraction of the radiative flux emitted by hot stars is absorbed by their winds and redistributed towards longer wavelengths. This effect, which leads also to the heating of the stellar photosphere, is termed wind blanketing. For…

太阳与恒星天体物理 · 物理学 2018-10-03 J. Krticka , A. Feldmeier

Massive clumps, prior to the formation of any visible protostars, are the best candidates to search for the elusive massive starless cores. In this work we investigate the dust and gas properties of massive clumps selected to be 70 micron…

星系天体物理 · 物理学 2017-07-26 A. Traficante , G. A. Fuller , N. Billot , A. Duarte-Cabral , M. Merello , S. Molinari , N. Peretto , E. Schisano

Wolf-Rayet stars are known to eject winds. Thus, when a Wolf-Rayet star explodes as a supernova, a fast, $>30,000$ km/s, shock is expected to be driven through a wind. We study the signal expected from a fast supernova shock propagating…

高能天体物理现象 · 物理学 2014-07-15 Gilad Svirski , Ehud Nakar

Hydrostatic models of Wolf-Rayet stars typically contain low-density outer envelopes that inflate the stellar radii by a factor of several and are capped by a denser shell of gas. Inflated envelopes and density inversions are hallmarks of…

太阳与恒星天体物理 · 物理学 2016-04-27 Stephen Ro , Christopher D. Matzner

In high mass X-ray binaries (HMXBs), an accreting compact object orbits a high mass star which loses mass through a dense and inhomogeneous wind. Using the compact object as an X-ray backlight, the time variability of the absorbing column…

高能天体物理现象 · 物理学 2020-11-25 I. El Mellah , V. Grinberg , J. O. Sundqvist , F. A. Driessen , M. A. Leutenegger

We seek to establish additional observational signatures of the effects of clumping in OB star winds. The action of clumping on strategic wind-formed spectral lines is tested to steer the development of models for clumped winds and thus…

太阳与恒星天体物理 · 物理学 2015-05-19 Raman Prinja , Derck Massa

We have analyzed the far-UV spectrum of two Galactic O4 stars, the O4If+ supergiant HD190429A and the O4V((f)) dwarf HD96715, using archival FUSE and IUE data. We have conducted a quantitative analysis based on the two NLTE model atmosphere…

天体物理学 · 物理学 2008-11-26 J. -C. Bouret , T. Lanz , D. J. Hillier

In the presence of strong clustering, low-resolution surveys measure the summed contributions of groups of sources within the beam. The counts of bright intensity peaks are therefore shifted to higher flux levels compared to the counts of…

天体物理学 · 物理学 2009-11-10 M. Negrello , J. Gonzalez-Nuevo , M. Magliocchetti , L. Moscardini , G. De Zotti , L. Toffolatti , L. Danese

We review the effects of clumping on the profiles of resonance doublets. By allowing the ratio of the doublet oscillator strenghts to be a free parameter, we demonstrate that doublet profiles contain more information than is normally…

天体物理学 · 物理学 2007-08-08 D. Massa , R. K. Prinja , A. W. Fullerton