We often think of stars as things that do not move much, but in some galaxies, that is far from being a universal truth. New observations made by NASA's powerful Chandra X-ray Observatory reveal that some stars are routinely plucked from their own host galaxies and sent flying back into space.
The researchers saw dozens of pairs of binary stars that had been, for lack of a better term, evicted from their homes after one of the two stars explodes in a supernova.
The NASA telescope observed several binary pairs, which are two stars that orbit each other in the heart of a star system, being ejected far from their homes by the force of one of the stars that explode.
When one of the stars explodes and then collapses on itself to become a dense neutron star, the asymmetric force of that action can cause the star to come out of its established position. As the neutron star recedes, its gravity pulls its binary companion, sending both stars on a path out of their own galaxies.
"It's like a guest who is asked to leave a party with a troubled friend," Xiangyu Jin, lead author of the research, said in a statement. "The companion star in this situation is dragged out of the galaxy simply because it is in orbit with the star that became a supernova."
There is nothing that the companion star can do, but move on with the journey, and the team of researchers using Chandra's data has already detected about 30 pairs of stars from the Fornax cluster of galaxies that seem to be moving away from their homes. to this phenomenon.
In the future, researchers hope to use additional data from Chandra to detect other pairs of evicted stars that are simply too faint to detect using existing data. Longer observation campaigns could change that, revealing additional binary pairs that are thrown into space.
Image source: NASA / CXC / Nanjing University / X. Jin et al.