All Questions
Tagged with black-holes binary-stars
34
questions
16
votes
3
answers
2k
views
Time dilation effects at the center of a binary black hole system
Imagine two identical black holes in a circular orbit, and Alice is smack-dab in the middle of the system (at the barycenter). Bob is at infinity.
Let's assume that Alice and Bob are stationary ...
- 779
16
votes
3
answers
41k
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How do we determine the mass of a black hole?
Since by definition we cannot observe black holes directly, how do astronomers determine the mass of a black hole?
What observational techniques are there that would allow us to determine a black ...
grassman
14
votes
7
answers
2k
views
Binary Black Hole Solution of General Relativity?
This is rather a technical question for experts in General Relativity. An accessible link would be an accepable answer, although any additional discussion is welcome.
GR has well known solutions ...
- 4,743
9
votes
3
answers
2k
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How do inspiraling black holes get closer?
In Newtonian mechanics, binaries are stable. We here on earth are very glad that it will not emit its angular momentum and spiral into the sun. What is different about the black holes and neutron ...
- 745
9
votes
2
answers
218
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Two charged black holes in equilibrium
Consider a pair of (possibly rotating) charged black holes with masses $m_1$ and $m_2$, and like charges $q_1$ and $q_2$. It seems that under certain conditions gravitational attraction should exactly ...
Squark
8
votes
2
answers
959
views
In which direction would gravitational waves be emitted when two black holes colide?
Imagine two black holes on the x-axis coming together at the origin (not rotating around each other, just falling towards each other).
In which direction would the most intense gravitational waves be ...
user84158
7
votes
1
answer
283
views
Theoretical solution to binary black hole merger based on Hawking and Ellis
Following Hawking and Ellis, Chapter 9, Fig. 60, Pg. 322, the following figure is meant to illustrate the contrast between apparent horizons and event horizons in the case of a binary black hole ...
- 245
6
votes
2
answers
715
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Can two relativistic black holes' event horizons overlap and separate again?
I have read this question:
What I have not seen is a purely classical argument for the non-separation of a black hole merger. One can obviously take the time reversed spacetime manifold of a merger ...
- 29k
6
votes
1
answer
91
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Extreme Mass Ratio Inspirals and GWs cycles
I was reading through the following paper GRMHD study of accreting massive black hole binaries in astrophysical environment: A review. Therein, we have the following image
It is not quite clear how ...
- 1,213
6
votes
2
answers
1k
views
What happens to the angular momentum of two merging black holes?
Suppose that two black holes of roughly equal mass in a binary system, formed from say a large mass stellar binary system, are in orbits around their center of mass. Further, suppose that we are ...
- 545
5
votes
2
answers
221
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Black holes: Is merger inevitable when horizons touch?
I watched a simulation of the binary black hole merger of 2019 April 12
https://www.ligo.caltech.edu/video/ligo20200420v1
When the "apparent horizons" (their terminology; are those ...
- 265
5
votes
1
answer
423
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Is there an approximate expression for the force between two black holes?
Just curious: is there an approximate expression for the gravitational attraction between two Schwarzschild black holes of masses $M$ and $m$, held without relative speed at some center to center ...
user85598
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
4
votes
1
answer
87
views
Do we use transit photometry to look for a black hole star binary systems?
What would a light curve look like for a black hole transiting a star? Initially I thought it would bend all light essentially blacking out a star but we would probably still detect some however the ...
- 1,348
4
votes
0
answers
85
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Hills Mechanism
The Hills mechanism postulates that when a stellar binary system is perturbed by a supermassive black hole (SMBH), the tidal forces at play result in the capture of one star while simultaneously ...
- 1,213