A head-on collision between galaxies has created a vast, cosmic triangle in deep space glittering with star formation in a new image captured by the Hubble Space Telescope.
The new photo, which NASA released Tuesday (Feb. 22), shows a pair of colliding galaxies known as called Arp 143 arranged in a what scientists described as a “space triangle,” where they are spawning a wave of star formation by sharing gas and dust.
“The two galaxies in this system collided head-on, fueling the triangular-shaped burst of star formation,” Hubble officials wrote in an image description. “The pair contains the distorted, star-forming spiral galaxy NGC 2445 at right, along with its less flashy companion, NGC 2444 at left.”
This wave of starbirth produced by the collision, officials added, appears to be rare due to the triangle shape of star formation visible in the image.
“Part of the reason for that shape is that these galaxies are still so close to each other, and NGC 2444 is still holding on to the other galaxy gravitationally,” participating astronomer Julianne Dalcanton, of the Flatiron Institute’s Center for Computational Astrophysics in New York and the University of Washington in Seattle, said in the Hubble statement.
Dalcanton added, “NGC 2444 may also have an invisible, hot halo of gas that could help to pull NGC 2445’s gas away from its nucleus. So, they’re not completely free of each other yet and their unusual interaction is distorting the ring into this triangle.”
Adding complexity to the collision is NGC 2444’s propensity to pull away strands of gas from the other galaxy, creating “streamers” of young, blue stars bridging the two galaxies. The streamer stars were created between 50 million and 100 million years ago, but will be stuck in space as the galaxies continue to pull apart from each other.
Another set of young stars, only 1 million to 2 million years old, is also forming in the heart of NGC 2445. Meanwhile, NGC 2444 is only filled with older stars; it lost its gas before the collision occurred, astronomers said.
The collision provides “a fantastic sandbox to understand star formation and interacting galaxies,” Elena Sabbi, a scientist at the Space Telescope Science Institute in Baltimore, added in the statement.