Fast Moving Star Shock Galaxy

Runaway stars, traveling at high speeds, can have huge impacts on their surrounding as they move through the Milky Way. NASA's Spitzer Space Telescope caught the effects of these fast moving stars in a newly released image that shows the arcs created as the star "shocks" the galaxy.

The star in question, named Kappa Cassiopeiae, is a "massive, hot supergiant moving at around 2.5 million mph relative to its neighbors," according to a press release announcing the observation. The streaky red glow left behind as the star moves is very unique. The residual glowing comes from structures called bow shocks, which are found in front of the fastest, most massive stars as they travel through space.

Bow shocks are formed when magnetic fields and wind flowing off of a star collide with the matter that fills the empty space between stars. The manner in which these shocks light up tell astronomers about the conditions around the star. Slower moving stars, like the Sun, have shocks that are invisible at all wavelengths, while the Kappa Cassiopeiae creates shocks that can be seen with infrared detectors.

Most notably, the shocks are created 4 light-years ahead of Kappa Cassiopeiea, which illustrates just how much of an impact its movement is having. For reference, Proxima Centuri, the closest star to Earth besides the Sun, is about 4 light-years away.

In the photograph, the bow shocks show up as a vivid red color, while the faint green color results from carbon molecules, called polycyclic aromatic hydrocarbons, in dust clouds that are being illuminated by starlight.

Some astronomers suggest the red filaments running through the nebula, crossing the bow shock, are tracing features of the magnetic field present in our galaxy. Because magnetic fields are invisible, astronomers rely on these chance bow shocks and similar cosmic events to reveal the structure of magnetic fields as they interact with the surrounding dust and gas.

While Kappa Cassiopeiae is visible to the naked eye, the bow shocks are only viewable in the infrared light spectrum.