This low-mass object could be a brown dwarf, making it difficult to classify.
Citizen scientists involved in NASA's Backyard Worlds: Planet 9 project have made an extraordinary discovery-an enigmatic object hurtling through space at an astonishing speed of 1 million miles per hour.
Volunteers combing through NASA data in search of new planetary bodies or celestial phenomena have found this object and it has been named "CWISE J1249."
Kabatnik, a participant from Nuremberg, Germany, expressed their thrill in a NASA press release: "I can't describe the level of excitement. When I first saw how fast it was moving, I was convinced it must have been reported already."
According to NASA, CWISE J1249 is zooming out of the Milky Way at about 1 million miles per hour. But it also stands out for its low mass, which makes it difficult to classify as a celestial object. It could be a low-mass star, or if it doesn't steadily fuse hydrogen in its core, it would be considered a brown dwarf, putting it somewhere between a gas giant planet and a star.
Ordinary brown dwarfs are not that rare. Backyard Worlds: Planet 9 volunteers have discovered more than 4,000 of them! But none of the others are known to be on their way out of the galaxy.
This new object has yet another unique property. Data obtained with the W. M. Keck Observatory in Maunakea, Hawaii, show that it has much less iron and other metals than other stars and brown dwarfs. This unusual composition suggests that CWISE J1249 is quite old, likely from one of the first generations of stars in our galaxy.
Why does this object move at such high speed? One hypothesis is that CWISE J1249 originally came from a binary system with a white dwarf, which exploded as a supernova when it pulled off too much material from its companion. Another possibility is that it came from a tightly bound cluster of stars called a globular cluster, and a chance meeting with a pair of black holes sent it soaring away.
"When a star encounters a black hole binary, the complex dynamics of this three-body interaction can toss that star right out of the globular cluster," says Kyle Kremer, incoming assistant professor in UC San Diego's Department of Astronomy and Astrophysics.