Why the excess of young stars close to Milky's supermassive BH?

In summary, a recent paper published in Astrophysical Journal discusses the presence of young stars in the vicinity of the super-massive black hole (SMBH) at the center of our galaxy. The authors propose that the young stars are a result of dynamical interactions between two stellar discs at larger radii, causing individual stars to achieve high eccentricities and be ejected towards the SMBH. This process may also explain the presence of hyper-velocity stars in the Milky Way halo. The possibility of galactic ejection in spawning new bodies is often overlooked in modern cosmology.
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marcus
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I happened to see this and thought someone here might be interested
It has been accepted for publication in Astrophysical Journal and it suggests a reason for something I didnt know about---there are unexpectedly many young stars clustered around the vicinity of the SMBH at the center of our galaxy.

some nice animations of the stars orbiting the SMBH are available, we had a thread about that several years back
if I remember correctly, the SMBH is about 2-3 million solar masses. that part is old news.

BTW I think is impressive that they can observe in there, in the heart of the galaxy and see individual stars. But mostly it strikes me as curious that there should be an excess of very young ones. These authors propose a possible reason

http://arxiv.org/abs/0807.2239
Origin of the S-Stars in the Galactic Center
Ulf Löckmann, Holger Baumgardt, Pavel Kroupa
4 pages, 4 figures, accepted for publication in ApJ Letters
(Submitted on 14 Jul 2008)
"Over the last 15 years, around a hundred very young stars have been observed in the central parsec of our Galaxy. While the presence of young stars forming one or two stellar discs at approx. 0.1 pc from the super-massive black hole (SMBH) can be understood through star formation in accretion discs, the origin of the S-stars observed a factor of ten closer to the SMBH has remained a major puzzle. Here we show the S-stars to be a natural consequence of dynamical interaction of two stellar discs at larger radii. Due to precession and Kozai interaction, individual stars achieve extremely high eccentricities at random orientation. Stellar binaries on such eccentric orbits are disrupted due to close passages near the SMBH, leaving behind a single S-star on a much tighter orbit. The remaining star may be ejected from the vicinity of the SMBH, thus simultaneously providing an explanation for the observed hyper-velocity stars in the Milky Way halo."

I have no special knowledge about this, so I can't comment myself. But thought other people might be interested.
 
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Marcus, massive objects can be ejected from the centers of galaxies via gravitational slingshot or perhaps radiation recoil. The disruption (sudden mass ejection in a highly-dense region of a galaxy) might trigger rapid star-formation. Sudden mass discrepancies could encourage rapid accretion of otherwise smoothly- distributed materials and allow new stars to light up.

Modern cosmology concentrates on gravitation, mergers, etc, and for the most part ignores the possible role of galactic ejection in spawning new bodies. Galactic dynamics is really tough. We live for a very short time, and galaxies can span billions of years. Even with the large sample that we can access, our scientific basis is VERY thin.
 
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1. Why are there more young stars near Milky Way's supermassive black hole compared to other regions?

The main reason for this is the intense gravitational pull of the supermassive black hole. As the black hole pulls in surrounding gas and dust, it creates a dense and compact environment that is ideal for the formation of new stars. The gas and dust are able to collapse under the strong gravitational force, leading to the formation of new stars. This process is known as "starburst activity" and is commonly seen in regions near supermassive black holes.

2. Is there a correlation between the distance from the supermassive black hole and the age of the young stars?

Yes, studies have shown that there is a correlation between the distance from the supermassive black hole and the age of the young stars. The closer the stars are to the black hole, the younger they tend to be. This is because the gas and dust near the black hole are constantly being replenished, providing a continuous supply for star formation. Therefore, the stars closer to the black hole have had less time to age compared to those further away.

3. Are there any other factors that may contribute to the excess of young stars near the supermassive black hole?

While the strong gravitational pull of the black hole is the primary factor, there are other factors that may contribute to the excess of young stars near the supermassive black hole. These include the density of gas and dust in the surrounding region, the presence of nearby star clusters, and the dynamics of the galactic environment. These factors can also play a role in the formation and age of the young stars near the black hole.

4. How do we know that the young stars near the supermassive black hole are actually formed due to its gravitational pull?

Scientists have used various observations and simulations to confirm that the young stars near the supermassive black hole are indeed formed due to its gravitational pull. For example, observations of the gas and dust clouds near the black hole show signs of compression and heating, which are necessary for star formation. Additionally, simulations of galactic evolution have also shown that the presence of a supermassive black hole can lead to a higher rate of star formation in its immediate surroundings.

5. Can the excess of young stars near the supermassive black hole affect the stability of the Milky Way?

While the presence of a large number of young stars near the supermassive black hole may seem concerning, it does not pose a threat to the stability of the Milky Way. These stars are still relatively small and have not yet reached their full size and energy output. Additionally, the gravitational pull of the black hole is balanced by the gravitational pull of other stars and objects in the galaxy, maintaining its overall stability.

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