Astronomers gazed into the center of the Milky Way and discovered what looks to be a small spiral galaxy revolving daintily around a single big star, as like cracking open a cosmic Russian nesting doll.
The star is around 32 times as massive as the sun and lies within a gigantic disc of spinning plasma known as a “protostellar disc,” which is located about 26,000 light-years from Earth near the dense and dusty galactic core. (The disc is 4,000 astronomical units broad, or 4,000 times the distance between the Earth and the Sun.)
Throughout the universe, such discs serve as stellar fuel, allowing nascent stars to evolve into large, luminous suns over millions of years. But astronomers have never seen anything like it: a small galaxy orbiting uncomfortably near to the galactic center.
What Are The New Observations?
According to a new study published in the journal Nature Astronomy on May 30, the answers could be found in a mysterious object around three times the mass of the sun lying just outside the spiral disk’s orbit.
The researchers discovered that the disc does not appear to be moving in a way that would give it a natural spiral structure using high-definition data collected with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile.
The disc, they said, appears to be literally churned up by a near-collision with another body — like the mystery triple-sun-sized object that’s still visible nearby.
To test this theory, the researchers calculated a dozen possible orbits for the strange object and ran a simulation to determine if any of them might have taken it close enough to the protostellar disc to cause it to spiral.
What Did The Researchers Find?
They discovered that if the item have followed a precise path, it could have skimmed past the disc roughly 12,000 years ago, perturbing the dust just enough to produce the brilliant spiral form that can be seen today.
“The good agreement between analytical calculations, numerical simulations, and ALMA observations provide strong evidence that the spiral arms in the disc are relics of the intruding object’s flyby,” study co-author Lu Xing, an associate researcher at the Chinese Academy of Sciences’ Shanghai Astronomical Observatory, said in a statement.
The Significance Of This Research
This research not only provides the first direct photographs of a protostellar disc at the galactic core, but it also demonstrates how external objects can whip stellar discs into spiral geometries that are only visible on galactic scales.
This is because the Milky Way’s center is millions of times denser with stars than our part of the galaxy, near-miss events like this are likely to happen frequently there, according to astronomers.
That means our galaxy’s core could be crammed with tiny spirals just waiting to be discovered. For a very long time, scientists may not be able to reach the center of this cosmic nesting doll.