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Accretion: accretion discs

Stability of Accretion Discs around Magnetized Stars

Stability of Accretion Discs around Magnetized Stars

... inner regions of the disc may also be thermally unstable (e.g. [3] and [4]). However, these analyses dealt primar- ily with the evolution of small perturbations of the disc’s central temperature T and surface density Σ . ...

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Accretion discs as regulators of stellar angular momentum evolution in the ONC and Taurus Auriga

Accretion discs as regulators of stellar angular momentum evolution in the ONC and Taurus Auriga

... Accretion disc-regulated PMS AM evolution has not found unan- imous support. Certain studies have not observed a relationship be- tween stellar rotation and accretion disc indicators. However, these ...

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Global 3D MHD Simulations of Waves in Accretion Discs

Global 3D MHD Simulations of Waves in Accretion Discs

... A rotating star with a tilted dipole (or other non-axisymmetric) magnetic field exerts a periodic force on the inner part of the accretion disk which acts to excite di ff erent types of waves that propagate to ...

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Magnetic Fields In Astrophysical Objects

Magnetic Fields In Astrophysical Objects

... To understand the essence of the MRI instability in a disc, one can picture the weak magnetic field that resides in the disc as acting like a spring that tethers two elements in the disc together†. Figure 5 shows an ...

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Accretion and Current Discs Controlled by Strong Magnetic Field

Accretion and Current Discs Controlled by Strong Magnetic Field

... possess discs which could generate ...of accretion discs, and are accelerated and collimated hy- ...the accretion disc wind driven by MHD turbulent pressure and amplified by magneto-rotational ...

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A New Model for Black Hole Soft X-Ray Transients in Quiescence

A New Model for Black Hole Soft X-Ray Transients in Quiescence

... These studies provide a warning that it is important to allow for the low eciency of advection-dominated ows when estimating the mass accretion rates of accreting black holes. When an accreting black hole is seen ...

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Disk accretion onto a magnetized star

Disk accretion onto a magnetized star

... Abstract. The problem of interaction of the rotating magnetic field, frozen to a star, with a thin well conducting accretion disk is solved exactly. It is shown that a disk pushes the magnetic field lines towards ...

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On the orbital periods of the AM CVn stars HP Librae and V803 Centauri

On the orbital periods of the AM CVn stars HP Librae and V803 Centauri

... 2002), looks remarkably similar to that of AM CVn (Roelofs et al. 2006b); it shows relatively simple ‘S-waves’ in the He i 4387, He i 4471 and He i 4921 lines, as well as in the Mg ii 4481 line. Like in AM CVn and other ...

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Detection of accretion X rays from QS Vir : cataclysmic or a lot of hot air?

Detection of accretion X rays from QS Vir : cataclysmic or a lot of hot air?

... the accretion efficiency is of the order of ...wind accretion unlikely. A lack of accretion disk signatures also presents some difficulties for direct Roche lobe ...

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Study of Solid Accretion Formation inside Pyrometallurgical Vessels by a Wax Model and Similarity Conversion for Gas Bottom Blown Process

Study of Solid Accretion Formation inside Pyrometallurgical Vessels by a Wax Model and Similarity Conversion for Gas Bottom Blown Process

... iron accretion sitting on the refractory lining via appropriate bottom-blown ...the accretion can protect the refractory lining from being eroded by the back attack of gas ...generate accretion with ...

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High mass star formation through filamentary collapse and clump fed accretion in G22

High mass star formation through filamentary collapse and clump fed accretion in G22

... current accretion rates are sustained. This high accretion will double the mass of the hub region in about six free-fall times where the free-fall time is about ...high accretion may not be ...

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Accretion Models of Gamma‐Ray Bursts

Accretion Models of Gamma‐Ray Bursts

... involve accretion onto a compact object, usually a black hole, at a mass accretion rate of order a fraction of a solar mass per ...the accretion disk is larger than a few tens or hundreds of ...

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Mass-loaded spherical accretion flows

Mass-loaded spherical accretion flows

... Accretion on interstellar and even intergalactic scales is of relevance in a variety of astrophysical sources including ac- tive galactic nuclei surrounded by stellar clusters (e.g., David et al. 1987) and cooling ...

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X Shooter study of accretion in Chamaeleon I

X Shooter study of accretion in Chamaeleon I

... Mass accretion rate as a function of mass for the whole Chamaeleon I sample of Class II discussed here (red filled stars for accreting objects and empty stars for non-accreting objects) and for the Lupus sample of ...

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Continuum reverberation mapping of AGN accretion disks

Continuum reverberation mapping of AGN accretion disks

... We show recent detections of inter-band continuum lags in three AGN (NGC 5548, NGC 2617, and MCG + 08-11-011), which provide new constraints on the temperature profiles and absolute sizes of the accretion disks. ...

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Radiative transfer in accreting environments

Radiative transfer in accreting environments

... In each of these observations, either the innermost regions of the accretion flow or the base of the jets are implicated in the production of the circular polarization. In the context of the former, general ...

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Accretion flows in compact binary stars

Accretion flows in compact binary stars

... T his ch ap ter describes tim e-resolved optical spectroscopy of EX H ya. T h e p rin c i­ pal optical spectroscopic features of the sta r are bro ad hydrogen em ission lines, show ing double-peaked s tru c tu re and a ...

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The Orbital Modulation for the Spectrum and Mass Accretion Rate in Circinus X 1

The Orbital Modulation for the Spectrum and Mass Accretion Rate in Circinus X 1

... Cir X-1 is an NSXB in which both radio and X-ray outflows (jets) have been observed. Fender et al. [21] observed its ultra-relativistic radio outflows and found that the velocity of the outflow is comparable to the fast- ...

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Accretion by the Galaxy

Accretion by the Galaxy

... the discs of such galaxies is contributed by detected gas, so much more gas has been turned into stars than the discs currently ...constant accretion of relatively metal-poor gas to explain why there ...

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The accretion dynamics of EX Lupi in quiescence : the star, the spot, and the accretion column

The accretion dynamics of EX Lupi in quiescence : the star, the spot, and the accretion column

... an accretion scenario where an increased rate requires more material coming from more distant regions in the disk and results in the heating of a larger part of the accretion ...increased accretion, ...

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