The Deepest Images Yet of The Galactic Center Reveal a Beautiful Cosmic Dance

[Judi Lynn]

Stars orbiting the galactic center. (ESO/GRAVITY collaboration)

MICHELLE STARR 15 DECEMBER 2021
In the heart of the Milky Way, stars tread a complex measure.


Bound by the gravitational field of the supermassive black hole in the galactic center, Sagittarius A*, a group of stars known as S-stars swoop on wild, years-long orbits. These orbits were recently studied to measure Sgr A*, a result that won the scientists involved a Nobel prize in physics.

But that doesn't mean the work was done, and now a team of researchers led by one of those scientists, Reinhard Genzel of the Max Planck Institute for Extraterrestrial Physics in Germany, has unveiled the fruits of their latest gaze into the abyss.

So deep are these newly captured images, that the team has identified an entirely new S-star, named S300, and refined estimates of the distribution of mass in the galactic center.

"We want to learn more about the black hole at the centre of the Milky Way, Sagittarius A*," Genzel explains.

. . .

More:
https://www.sciencealert.com/the-deepest-images-yet-of-the-galactic-center-reveal-a-beautiful-cosmic-dance

[brush]

1. This is new info. So what are these new stars orbiting?

Last edited Wed Dec 15, 2021, 01:54 PM - Edit history (1)

And does our Sun orbit also and if so what?

Also, do all spiral galaxies have a black whole at their center?

Rotation and orbiting/revolving around seem to be the building block that holds everything together and generates energy in the universe from electrons, protons and neutrons to moons rotating around planets and planets rotatiing round stars to galaxies revolving around black holes at their center.

Wonder what whole galaxies including their black holes revolve around?

[FreepFryer]

2. I thought they were orbiting the center of mass of the galaxy

But I think a singularity would make the action too close to the center either invisible or otherwise distorted. I imagine they are gravitationally coattracted, but it would be amazing if that was indeed the ostensible galactic center the S stars were orbiting in the image and sim.

[jaxexpat]

3. I think they're "sling shotting" in their near collision orbit around the super massive black hole.

Speculation is whether their orbit could be sustainable in the longer term. The gravitational interaction between themselves and the black hole makes for quick and highly eccentric orbit cycles. The speed of motion is critical. Because the nearest exposure of the stars to the black hole's gravity stretches them to the point of tearing, then their movement away from the black hole allows them opportunity to reassemble themselves. The cause and effect they share with the shroud of gas and dust they dwell within in inconclusive as well. Is the black hole removing the shroud material piecemeal with every degenerative pass? I've heard that they're multi-binary stars as well. If that's the case, is the multi-star object itself the "current state" of a single star being inevitably disintegrated and consumed by the black hole?

Hey, I don't know.

[brush]

4. Thank you for the input. It's a lot to think about.

[brush]

5. Thanks. So much to think about.

[Igel]

6. The galactic center of mass doesn't have to be Sgt A*.

Might be displaced.

Thing about orbits (like gravity on Earth) is that if the distribution of mass is even outside of your orbital radius (or distance from the Earth's center of mass) doesn't count.

To the extent that the Earth is a sphere there's no perceived gravity at the Earth's center--you're pulled equally well in all directions, so there's no net force and you're in dynamic equilibrium. Perturb your position, and you'd be drawn back towards the center.

Same for the net force on something at the center of the MW, were it completely symmetrical (and your orbit lie in the galactic plane).

No, Andrea Ghez's gif from the early 2000s nailed it (that's the UCLA/Keck Galactic Center workgroup's gif, but she's usually been the face of the GCW), and the updated one with a longer dataset from the mid 2010s refined it. This is just more detail.

I'd expect that the orbits of the stars slingshotting aren't long-term stable. In some cases they'll interact with each other, but ultimately gravitational waves will bleed off their energy (and I assume that frame dragging by the BH will have some effect on those with the closest orbits, but no way I'm going to say what that effect would be).