Questions tagged [binary-stars]
Binary stars are a system of two stars rotating around their center of mass, as opposed to single stellar systems such as our solar system.
23
questions
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
36
votes
3
answers
23k
views
Might a planet perform figure-8 orbits around two stars?
Might a planet perform figure-8 orbits around two stars?
I'm thinking that if the two stars were equal mass (and not orbiting each other) then a planet that were to go right between them would ...
- 4,545
5
votes
2
answers
220
views
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
0
votes
1
answer
299
views
Binary System in General Relativity: Analytical Metric? [duplicate]
My question is quite simple, why an analytical metric can't be found for a static binary system, even for a system under the Schwarschild condition : low field, in the vacuum between the bodies so $T_{...
- 11
16
votes
3
answers
41k
views
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
9
votes
4
answers
2k
views
Binary Star system with one star stationary?
Can a Binary Star system be possible where in one star is stationary and the other star revolves around it? (Just like a planet revolving a star. i.e planets in the system and the star revolving ...
- 265
9
votes
1
answer
629
views
On what timescale does gravitational wave emission circularise an orbit?
Gravitational waves remove both energy and angular momentum from a binary orbit. Both rates are enhanced in non-circular (eccentric) orbits and I presume that (like tidal friction) the net effect will ...
- 133k
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
6
votes
2
answers
711
views
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
5
votes
3
answers
970
views
Ratio of masses of double star problem
I am currently studying Classical Mechanics, fifth edition, by Kibble and Berkshire. Problem 2 of chapter 1 is as follows:
The two components of a double star are observed to move in circles of radii ...
- 889
2
votes
1
answer
553
views
What happens to the singularities of two black holes in the moment they merger?
Let's assume the merger of a binary black hole and consider especially the moment of the transition from the last stable orbit to the merger, i.e. the transition where two black holes form one black ...
- 1,589
2
votes
2
answers
164
views
Is there a model relating GW signal and luminosity of the merger / burst?
To understand fully the importance of the recent observation I would like to know if it is possible to infer the distance or luminosity (in whatever wavelength, or say, the overall power) of the ...
- 1,729
1
vote
1
answer
188
views
Event-Horizon Shape in a Binary System
I understand that a solitary black hole has a spherical event horizon.
I was wondering whether this still stands in a binary system of two (let's say equal mass) black holes? Could the proximity of ...
26
votes
3
answers
4k
views
What is the smallest distance possible between two stars?
If two stars of any type were to form near each other, how closely can they form before something prevents them from being two distinct stars?
- 6,015
12
votes
1
answer
645
views
Are the orientations of spin-axes and binary/planetary orbits random or is there any relationship with the Galactic plane?
In an answer to another question, a claim has been made that orbit/spin orientations are random (at least within our own Galaxy), except perhaps towards the Galactic centre.
I have dabbled in this ...
- 133k