(ORDO NEWS) — Astronomers have peered into the center of the Milky Way and discovered what appears to be a miniature spiral galaxy orbiting a single large star.
Even inside our galaxy, there are so many interesting and strange objects that scientists never cease to be amazed.
The star, located about 26,000 light-years from Earth, near the dense center of the galaxy, is about 32 times more massive than the Sun, and lies within a huge disk of swirling gas known as the “protostellar disk.”
The disk itself is about 4,000 astronomical units wide, or 4,000 times the distance between the Earth and the Sun.
Galaxy within a galaxy
Such disks are widespread in the universe – they concentrate gases and cosmic dust particles that help young stars grow over millions of years.
But astronomers have never before seen these disks take on the shape of a spiral and be right next to the center of the galaxy.
How did this mini-spiral come about, and are there others similar to it? According to a new study published in the journal Nature Astronomy, the answers may lie in a mysterious object, about three times as massive as our Sun, lurking outside the spiral disk’s orbit.
Using high-definition observations taken with the ALMA telescope in Chile, the researchers found that the disk’s trajectory prevents it from naturally spiraling.
Most likely, according to astronomers, the disk was formed as a result of a collision with another body – perhaps a mysterious object three times as massive as the Sun, which can still be seen nearby.
To test this hypothesis, the team calculated a dozen potential orbits for the mysterious object, then ran simulations to see if any of those orbits could bring the object close enough to the protostellar disk to coil it into a spiral.
The scientists found that if this object followed one particular path, it could have passed by the disk about 12,000 years ago, spinning it enough to give the object a spiral shape.
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