06/22 11:00
Astronomers have discovered what appears to be a miniature galaxy orbiting a single large star in the heart of the Milky Way.
Scientists spotted the strange object orbiting a large star located about 26,000 light-years from Earth, near the center of the galaxy.
The star itself is about 32 times larger than the sun, and is contained within a “protostellar disk”, an enormous disk of swirling gas. This stellar disk is about 4,000 astronomical units wide – or 4,000 times the distance between the Earth and the Sun, and is an essential component of star formation.
These bodies, also known as accretion disks, constantly feed gas in protostars from the environment that serves as stellar fuel for young stars to feed and grow into the bright sun.
However, astronomers were shocked when they discovered a miniature galaxy inside the disk, orbiting near the center of the Milky Way.
In a new study published in Nature Astronomy, scientists say they are exploring the mysteries behind this spiral galaxy, and believe the answers lie in a mysterious object, about three times the size of our sun, found outside the spiral disk’s orbit.
The scientists used high-resolution observational data from the ALMA (Atacama Large Millimeter / Sub-millimeter Array) in Chile, and found that the gas disk was stirred up by a close collision with another object, possibly the mysterious three-dimensional object that is still visible near it, which led to the formation of Helical arms.
This discovery indicates that the formation of massive stars may be similar to the formation of low-mass stars, through accretion disks and flight near the body.
In order to test this hypothesis, astronomers analyzed dozens of possible orbits in which the mysterious object might have been.
The team then ran simulations to see if any of these orbits could bring the object close enough to the stellar disk to spiral.
Scientists were able to successfully reproduce the entire history of the flying object by the disk more than 10,000 years ago, and found that if the object followed one specific path, it could have crossed the disk about 12,000 years ago, causing the dust to perturb enough to create the vibrant spiral shape. which we see today.
Scientists say that these findings prove that stellar disks in the early evolutionary stages of star formation are often whipped up by external dynamic processes such as fly-bys of an object, which can affect how stars and planets form.
Scientists believe that such flybys may have occurred in our solar system as well, when the binary star system known as the Scholz star flew close to the solar system about 70,000 years ago.
It is possible that this object penetrated the Oort cloud and sent comets into the inner solar system.
“The composition of this massive protostar is similar to that of its lower-mass cousins like the Sun, with accretion disks and flyby events nearby. Although stellar masses differ, some of the physical mechanisms in star formation can be similar,” Dr. Lu said. This provides important clues to solving the mystery of massive star formation.”