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.
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Why does a black hole grow when it consumes matter? Isn't this a contradiction?
I've been thinking about this for a while but can't get my head around it.
A black hole's mass is such that its gravity can overcome light. Its event horizon, as I see it, is the boundary up to which ...
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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 ...
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Four-momentum of a photon emitted from an accretion disk
Consider a non-rotating compact object surrounded by a revolving accretion disk. A distant observer sees the disk in an edge-on position. The center of the disk may be taken as the origin of $r-\theta-...
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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 ...
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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 ...
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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 ...
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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 ...
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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 = \...
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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 ...
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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 ...
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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?...
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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 ...
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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 ...
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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.
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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 ...
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