The phenomenon is similar to that seen when a speeding boat pushes through water on a lake, the ‘bullet’ star travels through the dense gas and powerful stellar winds.
“Finding these stars is a complete surprise because we were not looking for them. When I first saw the images, I said ‘Wow. This is like a bullet speeding through the interstellar medium.’ Hubble’s sharp ‘eye’ reveals the structure and shape of these bow shocks.”
Depending on their distance from Earth, the ‘bullet-nosed’ could be 100 billion to a trillion miles wide (the equivalent of 17 to 170 solar system diameters).
Assuming their youthful phase lasts only a million years and they are moving at roughly 112,000 miles an hour, the stars have traveled about 160 light-years.
There are two possible ways this phenomenon happened. One way is if one star in a binary system exploded as a supernova and the partner got kicked out. Another scenario is a collision between two binary star systems. One or more of these stars could have picked up energy from the interaction and escaped the cluster.