Researchers find fleeing object from the Milky Way – and are puzzled

2024-08-25 13:26:29

Galactic Outlier

Astronomers discover unusual object in the Milky Way

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25.08.2024 – 13:23Reading time: 2 min.

This artist’s impression shows a hypothetical white dwarf (left) that exploded as a supernova, catapulting “CWISE J1249” out of the star system. (Quelle: W.M. Keck Observatory / Adam Makarenko)

An unknown object is escaping from the Milky Way at a rapid speed. Astronomers are puzzling over what it could be.

Amateur astronomers have discovered an object that is moving out of our galaxy at 1.6 million kilometers per hour. The US space agency NASA reports this on its website. There are several theories about the origin of the celestial body, it says.

The object was discovered several years ago by amateur astronomers participating in a NASA-funded space exploration project called “Backyard Worlds: Planet 9”. The research group used images taken with the WISE (Wide-Field Infrared Survey Explorer) space telescope, which has been searching for objects in our cosmic neighborhood since 2010.

The WISE space telescope observes near-Earth asteroids and comets. (Source: IMAGO / NASA)

“I can’t describe the excitement,” said Martin Kabatnik of Nuremberg, who is considered the co-discoverer of the object called “CWISE J124909.08+362116.0.” “When I first saw how fast it was moving, I was convinced that it must have already been reported.”

Further observations with telescopes around the world helped the amateur scientists to confirm their discovery and describe the object in more detail. The researchers were able to publish their results in the renowned journal “Astrophysical Journal Letters”.

According to this, “CWISE J1249” stands out due to its low mass, which is why it could be a so-called brown dwarf. These objects are often larger than a planet, but smaller than a star.

Because they are unable to maintain stable nuclear fusion, they are often referred to as “failed stars.” Over the course of their lives, these celestial objects cool down more and more and shine less brightly than a star.

Little iron and other metals

Further investigations show that “CWISE J1249” could belong to the first generation of stars in the Milky Way. This is indicated by the unusual composition of the celestial body. According to the researchers, the object contains much less iron and other metals than other known stars and brown dwarfs.

Brown dwarfs are smaller than stars and shine less brightly than them. (Source: IMAGO / StockTrek Images)

This theory could explain the composition of “CWISE J1249”, but not why it is escaping from the Milky Way at such a high speed. Most other objects of this size – more than 4,000 brown dwarfs have been discovered by amateur astronomers – move in orbits around the center of our galaxy.

According to the researchers, there are two theories for its unusual behavior: One is that the celestial body comes from a binary star system with a so-called white dwarf. This could have exploded as a supernova after it pulled the material from its companion and thereby ejected “CWISE J1249” from the star system.

The other possibility could be that “CWISE J1249” originates from a closely connected globular cluster that has encountered a pair of black holes over the past billions of years. The dynamics of this three-body interaction could have ejected the celestial object from the cluster, it is said.

Scientists now want to find out which of these is possible. NASA writes that only further observations of the celestial object could provide further clues.