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tony873004
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I don't have that data. I imagine you'll just have to approximate based on the color of the stars.
Would it be possible for you to provide me a list of body masses, and a snapshot of their coordinates and velocities? I'd love to try this out.Janus said:Using my normal POV-Ray method, here's an animation that gives a more three dimensional perspective of the respective orbits.
What metric does that simulator use, Newtonian or relativistic? Orbits around black holes can look much different under Einstein than they would under Newton as shown in this thread where the same initial conditions give very different results for Newton and Einstein: Black hole orbitsJanus said:the orbit simulator I have on my computer (Gravsim)
I think bearing in mind the very short observational period we are working with, any effects due to particles outside about ##10R_s## to ##100R_s## would be "lost in the noise", so I'm comfortable with a Newtonian approach. Not that I feel we have much choice in the matter ;)Yukterez said:But that depends on which effect is stronger: the mutial attraction of the orbiting stars reative to each other or the relativistic effect of curved spacetime generated by the central black hole (which is only the case if the orbits get close enough so that the ratio rs/r is not neglible).
When the observed velocity at the perihelion at 10rs is for example 0.2236068c there would be a notable difference between the Newtonian and the relativistic orbit:m4r35n357 said:I think bearing in mind the very short observational period we are working with, any effects due to particles outside about ##10R_s## to ##100R_s## would be "lost in the noise", so I'm comfortable with a Newtonian approach.
We could simulate it in Schwarzschild metric (if the simulations we already have aren't already)m4r35n357 said:Not that I feel we have much choice in the matter
With the listed eccentricity, I get a precession of apsides of ~ 0.17 degrees per orbit. With a 14.53 year orbit, this works out to ~30500 years for the apsides to rotate a full 360 degrees. ( Compare this to the 43 seconds of arc per century precession for Mercury, which would take ~3,000,000 years to complete a full rotation.)Yukterez said:I see at Wikipedia that the lowest orbit has a semimajor axis of around 1000 Au while the rs of the black hole is only 0.1 Au. In that case there is no need for a relativistic simulation and Newton does the job.
Agreed, but my point was we don't have enough actual data to check our predictions accurately against (order of 15 year orbits).Yukterez said:When the observed velocity at the perihelion at 10rs is for example 0.2236068c there would be a notable difference between the Newtonian and the relativistic orbit:
Yes, I suppose we could use the potential (with extra term due to GR) in a n-body simulation. We would also need to consider interactions between stars that pass nearby each other around the perihelion (we'd need to use that potential for all the stars), so I'd call that a modified Newtonian analysis really.Yukterez said:So if the closest perihelion were at that distance it might be better to neglect the mutual attraction of the orbiting stars and threat them as test particles, but therefore take the relativistic metric of the black hole into account, but if the closest perihelion were at 100rs it's surely better to stay with Newton.We could simulate it in Schwarzschild metric (if the simulations we already have aren't already)
Sagittarius A* (Sgr A*) is a supermassive black hole located at the center of the Milky Way galaxy. It is estimated to have a mass of about 4 million times that of the Sun.
Scientists use a technique called astrometry to measure the positions and movements of stars around Sgr A*. This involves precise observations of the stars' positions over time using powerful telescopes.
The orbital parameters of the stars orbiting Sgr A* include their orbital period (the time it takes for them to complete one orbit), their orbital eccentricity (how elliptical their orbit is), and their orbital inclination (the angle of their orbit relative to Earth).
Studying the orbital parameters of stars around Sgr A* can provide valuable insights into the structure and dynamics of the Milky Way galaxy. It can also help us better understand the behavior of supermassive black holes and their influence on their surrounding environment.
Yes, in recent years, scientists have made significant advancements in measuring the orbital parameters of stars around Sgr A*. These observations have revealed that the stars' orbits are affected by the strong gravitational pull of the supermassive black hole, confirming Einstein's theory of general relativity.