All Questions
Tagged with accretion-disk astrophysics
38
questions
5
votes
1
answer
34
views
Why is the common envelope ejected in some accretor-donor systems?
As an example, let us consider a binary system of a neutron star and an evolved star (e.g. red giant) that has expanded, filled its roche lobe, and started the mass transfer onto the neutron star.
...
- 95
1
vote
0
answers
62
views
What determines the black hole accretion rate?
There is clearly a natural timescale to accrete matter around a black hole given by the balance of pressure and gravity, known as the Eddington luminosity. However, as I understand it, this is really ...
- 1,291
1
vote
1
answer
81
views
Rotating black hole
I know that everything that is shaped from gravity force is rotating, and gravity is a central force. but I want to know how can we detect that a black hole has an angular momentum? By which ...
- 39
6
votes
0
answers
75
views
Improving physics simulation of black hole accretion disk?
I have recently been working on software which uses ray tracing/marching to render a black hole in the Schwarzchild metric. I've implemented most everything that I originally set out to do, and I am ...
1
vote
1
answer
72
views
What happens when a helium white dwarf accretes enough matter?
What happens when a helium white dwarf accretes enough matter?
Say you have a white dwarf made of helium, what happens when it's core becomes dense enough to fuse helium and how massive would it have ...
- 2,908
2
votes
1
answer
757
views
Is a fusion process possible inside an accretion disk?
Is a fusion process possible inside an accretion disk? As the speed of matter inside an accretion disk approaches the speed of light can an incoming object collide with the disk material and cause a ...
- 1,815
3
votes
1
answer
73
views
How can supersonic accretion flows exist in astrophysical scenarios?
I often hear about supersonic accretion flows in astrophysical scenarios: for example, the inner parts of the accretion disk around a supermassive black hole or cold filaments accreting into galaxies ...
- 205
1
vote
1
answer
149
views
Why does the jet come out perpendicular to the accretion disc?
Why does the jet always come out perpendicular to the plane of the accretion disc around a black hole?
- 11.8k
1
vote
0
answers
30
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Some doubts regarding the Paczynsky-Wiita potential for modeling accretion disk around Schwarzschild black holes?
I am presently studying accretion processes around Schwarzschild black holes and for this purpose I am reading the classic paper by Paczynsky and Wiita (1980). In this paper, the authors define the ...
- 2,015
2
votes
0
answers
48
views
Is an exact description of accretion flow possible very close to a Schwarzschild black hole?
While modelling accretion disks around Schwarzschild black holes, various pseudo-Newtonian potentials are prescribed and then compared to general relativistic results. Though the pseudo-Newtonian ...
- 2,015
4
votes
3
answers
262
views
What happens to the accretion disk when two black holes merge?
I'm aware that accretion disks around black holes are formed from the swirling mass of matter that is slowly being stripped of its atoms, but what happens to it when two black holes merge? I was ...
- 87
1
vote
1
answer
108
views
AGN accretion disk double peak explained?
I have a question to the following lecture: https://ned.ipac.caltech.edu/level5/Fabian4/Fab2_2.html
In Figure 3 it says that a narrow annuli of a Newtonian disk should alrdy show a double peak ...
- 11
5
votes
1
answer
658
views
Effective potential for Kerr geometry
In the review Foundations of Black Hole Accretion Disk Theory, the authors defines an effective potential for Kerr geometry as (Chap. 2, eqn. 23)
$$\mathcal{U}_{eff}=-\frac{1}{2}\ln\left|g^{tt}-2lg^{t\...
- 2,015
0
votes
0
answers
33
views
Newtonian/Relativistic Solutions of Fluid Disks in orbit around a massive body
I have been trying to make an RMHD (Relativistic Magneto-Hydro Dynamics) Set-up of a Disk around a Massive Rotational Body.
The initial paper I have been studing a paper which uses a Fishbone & ...
- 231
1
vote
0
answers
29
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What are Quasi-Periodic Oscilations and how can they be used to determine the mass of black holes?
Quasi-Periodic Oscillations (QPOs) are observed in almost all accreting systems and they provide an essential tool to explore accretion flows from compact objects.
But I couldn't understand what ...
- 133