Occasionally, the Milky Way throws a star. The evacuated star is usually thrown out of a chaotic zone in the center of the galaxy, where the supermassive black hole (SMBH) lives. But at least one of them was expelled from a relatively calm galactic disc, the discovery of which astronomers rethink this whole phenomenon of starvation.
"This discovery dramatically changes our perception of the origin of fast-moving stars."
Monica Valluri, professor of research at the Department of Astronomy at the U-M College of Literature, Science and Arts
The star referred to is a fast-moving star, or what is also called a hyper-light star. Hyperpower stars are rare in our galaxy. The first one was discovered in 2005, and so far researchers have found less than 30 of them. They travel more than 1
To understand what is happening, take a look at the overall structure of the Milky Way.
Galactic bulge is in the center, and deep in the center of this convex is the SMBH of our galaxy Sagittarius A * (Sag. A-star.) Spreading the galactic disk around itself, made to the spiral arms of the galaxy. Less important in this study are star halo and globular clusters.
When a star is thrown out of the galaxy, it is usually a star of a binary pair. Scientists believe that as a binary pair is too close to the SMBH and its superimposed gravity, the hole captures one of the stars. Another star is thrown into space in the "gravitational horn". The black hole should be supermassive, since they only have a sufficiently powerful gravity to accelerate these missing stars to such high velocities. from the University of Michigan discovered one hypertrophytic star, which seems to have been thrown out of a stellar disk, and not galactic bulge.
Monica Vallurii and Kohhea Hattori tracked a hypertrophic star called
LAMOST-HVS1, a hyper-weloid star that is closer to the Sun any other. They used one of the Magellan telescopes to measure the speed and position of the star. They then joined other colleagues and merged their data with the data from the ESA Gaia mission to trace the trajectory of hypertension back to its origin. They were surprised when the origin of the star was not a bulge but a galactic disk.
"This discovery radically changes our perception of the origin of fast-moving stars," said Monica Valluri, a professor at the Department of Astronomy at the U-M College of Literature, Science and Arts. "The fact that the trajectory of this massive fast-moving star arises in a disc, not in the Galactic Center, indicates that very extreme environments necessary for the removal of fast-moving stars may occur elsewhere than around supermassive black holes."  Kohay Hattori, postdoctoral researcher, University of Michigan.
"We thought this star came from the center of the galaxy. But if you look at its trajectory, it's clear that it is not connected with the center of the Galaxy, "said Hattori. "We should consider other possibilities for the origin of the star."
What would these opportunities be?
The authors are not sure about this point. One of the possibilities is a meeting of another type. The fugitive star may have collided with the whole mass of other massive stars and was thrown out by the complex interaction of gravity
. But nothing travels as fast as LAMOST-HVS1. Star clusters branch out at a distance of 40-100 km / s (25-62 km / sec), but none of them nearer to 500 km / sec, for which this star travels.
Another, the more exotic possibility is Black hole. There may be other, intermediate black holes in a galactic disk with enough gravity to bring the star into space. But this is a bit more than an assumption.
If this is a stellar cluster thrown by LAMOST-HVS1, then nobody has seen it yet. The stellar hypervission came from the Normal spiral arm, an area not associated with known massive stellar clusters. However, this area is well covered with dust. There may be a cluster of sufficient mass to remove the star.
If astronomers could find a massive accumulation there, it could show that all the hypertrophic stars were thrown out of meetings with massive clusters, and the SMBH has nothing to do with it. Or, having here, a massive stellar cluster may have an intermediate black hole in its center, powerful enough to drive a star.
So far, however, the origin of LAMOST-HVS1 remains uncertain.