Questions tagged [accretion-disk]
An accretion disk is the disk around a compact star that accumulates matter from e.g. a companion star by the Roche lobe overflow or stellar wind transfer.
86
questions
0
votes
0
answers
5
views
What angle would frame dragging shove matter in the innermost accretion disk relative to the equatorial plane or orbit?
I understand that frame dragging will imbue momentum on plasma orbiting a black hole at close range.
My first question is - is this kinetic energy inserted very narrowly relative to the equatorial ...
- 1
1
vote
0
answers
52
views
Does a white hole forms accretion disk?
A white is time reversal of a blackhole at least mathematically, I know it can't exist but may I know if it can form accretion disc similar to those stellar mass black holes. Does it spins on it's ...
- 13k
1
vote
0
answers
51
views
Should we expect lightning-like phenomena as matter enters the accretion disk of a black hole?
As matter enters the accretion disk it will rapidly turn into superheated plasma. I would expect this to coincide with lightning-like phenomena due to the electric potential difference between this ...
- 1,775
2
votes
0
answers
39
views
Would an ionized accretion disk experience radial charge separation?
(Sorry if I'm using the wrong terms, but I've yet to find any search terms that seem related to what I'm thinking of. If I did know what to search for, I wouldn't be asking this question.)
Would an ...
- 1,269
0
votes
1
answer
113
views
Perfect Conducting (PC) and Perfect Insulating (PI) boundary conditions for magnetic induction in MHD problems in cylindrical coordinates
I understand the computational implementation of the PC and PI bcs in cartesian case. In terms of the magnetic field components for PI, we have $B_x = B_y = B_z = 0$, and for PC, we have $B_x = \...
- 23
2
votes
0
answers
41
views
Are these star - black hole binary pair illustrations art or physics?
It seems that every illustration of a black hole pulling matter off a star looks like this one from the Chandra X-ray Observatory website.
Or this one from Nature - Two black holes found in a star ...
- 41.1k
1
vote
1
answer
48
views
Space mission for experimental verification of frame-dragging in the strong-gravity limit
Frame-dragging is an important general relativistic effect that has been observed in the weak-field limit by the Gravity Probe B experiment for the gravitational field of the Earth.
Although the ...
- 2,015
0
votes
1
answer
105
views
Can stars gravitationally shield a black hole?
Is it possible to arrange a set of massive objects such as stars in orbit around a black hole such that objects of lesser mass cannot physically reach and fall into the event horizon of the black hole?...
4
votes
1
answer
178
views
Why don’t black rings exist in 3+1 dimensions?
In higher dimensions black holes can take different forms. Besides spheroids, there are also “black rings” which have a toroidal event horizon. However, in our 3+1 dimension no black ring solution has ...
- 1,455
-1
votes
2
answers
68
views
Star gets eaten and spit out?
How does material get swallowed and torn apart by a black hole and have its light vanish. But somehow the same material escapes years later. After its light couldn't even escape?
They watched it for ...
1
vote
0
answers
42
views
How would the Redshift of a Photon be influenced if it travels through a volumetric gas disk?
so me and a buddy have been working on a Black Hole render engine for quiet a while now. And at this point we have most of the technical stuff worked out. Which results in images like these;
Note, ...
- 308
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
2
answers
356
views
Why is the photon sphere spherical, but the accretion disk not?
As far as I understand, photons are massless, but are still subject to gravity, must follow the distortions of spacetime (including framedragging etc.), period.
Now the only answer on this site ...
- 29k
1
vote
1
answer
105
views
What does a black hole accretion disk look like edge on?
We have images of two black holes so far, with representations showing a deep black center where in-falling matter vanishes- how would that look side on? Would it be possible to even obtain an image ...
- 39
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
3
votes
1
answer
356
views
Neutrinos and black holes
As a new user I could not comment on Do neutrinos of any flavor get trapped in black holes?
My question is that the Ice Cube facility has mapped Neutrinos coming from black holes, as stated in ...
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 ...
0
votes
1
answer
35
views
If the BH accretion disk rotates near the speed of light should its EM-radiation in direction of rotation be highly blueshifted?
If the BH accretion disk rotates near the speed of light should its EM-radiation in direction of rotation be highly blueshifted? Maybe gamma blushifted if there weren't gravitational redshift?
- 2,255
0
votes
0
answers
53
views
Circular gravitational field
Why do all heavy masses in the universe always have circular gravitational field and why do objects 'falling' under their spacetime influence always fall in circles? For example, accretion disks ...
2
votes
0
answers
39
views
Would a black hole act as a particle accelerator between the photon sphere and the event horizon?
I'm trying to understand the behavior of photons between the photon sphere and the event horizon. Here is what I think I understand so far :
the radius of the PS is 1.5 times the Schwarzschild radius
...
- 21
5
votes
2
answers
150
views
Is accretion disc caused by frame dragging?
Is accretion disc around a Kerr black hole the result of its frame dragging?
- 1,161
2
votes
1
answer
67
views
What happens when a cool brown dwarf slowly accretes matter?
Let's imagine that we take a brown dwarf close to the minimum mass of a red dwarf.
Then let's allow it a few quadrillion years to cool.
Finally slowly accrete matter at a rate of say 1 Jupiter mass ...
- 2,908
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
0
votes
0
answers
34
views
Does some of accretion disk light make focal points above the black hole poles? [duplicate]
Does some of accretion disk light make focal points above the black hole poles?
- 1,815
1
vote
0
answers
76
views
Does the latest picture of EHT mean the end to the no hair theorem?
I couldn't help but noticing what looks like "hair" in the latest image from EHT.
Does this mean the end of the no hair theorem?
Pun intended but also a serious question.
- 25.3k
0
votes
0
answers
56
views
What ranges of $l$ and $m$ give the spherical harmonics for disk features?
The spherical harmonics represent a spherically symmetric basis and correspond to the eigenfunction solutions of the three-dimensional Laplacian. They take the form
$$ Y_l^m(\theta,\phi) = \sqrt{\frac{...
- 462
1
vote
1
answer
63
views
Are the particles in the accretion disk in free fall around the black hole?
I know that black hole can feed off the material in the accretion disk and gain mass, the accretion disk is also powered by the black hole to move at a fraction of speed of light. I am wondering are ...
- 13k