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Fastest star ever seen is moving at 8% the speed of light:
In the center of our galaxy, hundreds of stars closely orbit a supermassive black hole. Most of these stars have large enough orbits that their motion is described by Newtonian gravity and Kepler's laws of motion. But a few orbit so closely that their orbits can only be accurately described by Einstein's theory of general relativity. The star with the smallest orbit is known as S62. Its closest approach to the black hole has it moving more than 8% of light speed.
[...] For years, S2 was thought to be the closest star to SgrA*, but then S62 was discovered. As a team recently discovered, it's a star about twice as massive as the sun that orbits the black hole every 10 years. By their calculations, at the closest approach, its speed approaches 8% of the speed of light. That's so fast that time dilation comes into play. An hour at S62 would last about 100 Earth minutes.
Because of its proximity to SgrA*, S62 doesn't follow a Keplerian orbit. Rather than being a simple ellipse, it follows a spirograph motion by which its orbit precesses about 10 degrees with each cycle. This kind of relativistic precession was first observed with the orbit of Mercury, but only as a small effect.
Journal Reference:
Florian Peißker, Andreas Eckart, and Marzieh Parsa. S62 on a 9.9 yr Orbit around SgrA* - IOPscience, The Astrophysical Journal (2020) (DOI: 10.3847/1538-4357/ab5afd)
(Score: 0) by Anonymous Coward on Monday August 17 2020, @01:22PM (4 children)
If your space ship hyperspace jumped to this point of closest approach, what escape velocity do you need to escape the blackhole?
(Score: 0) by Anonymous Coward on Monday August 17 2020, @03:08PM
And when can we start mining black holes so that tech billionaires can keep little trophies made out of black hole pixie dust on their mantelpieces?
(Score: 0) by Anonymous Coward on Monday August 17 2020, @03:11PM
Only a little faster than the star is moving. I used a quick online calculator given the star's periapsis (closest approach) distance from Wikipedia, and the mass of the black hole and it came up with 21,000 km/sec, which is about 7% of the speed of light. Of course, the online calculator is just a simple Newtonian calculation and doesn't take into account all the factors going on with a supermassive black hole. But in general, speed at the periapsis of a highly elliptical orbit, which this one is, is only a little slower than the escape velocity.
At periapsis, the star is only about 2.4 billion km away from the black hole - that's closer than Uranus is to the Sun.
The linked article gives the speed of the star at about 8% of light speed - but both Wikipedia and the source paper list it at 10%. It's fast.
(Score: 3, Insightful) by https on Monday August 17 2020, @05:00PM (1 child)
A bit more than 0.08c, it looks like. Else that star wouldn't be in orbit.
Offended and laughing about it.
(Score: 2) by FatPhil on Wednesday August 19 2020, @05:45AM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves