Space Telescope Sees Shocking Behavior by Speedy Star

Roguish runaway stars can have a big impact on their surroundings as they plunge through the Milky Way, as seen in a new image from NASA’s Spitzer Space Telescope.

Roguish runaway stars can have a big impact on their surroundings as they plunge through the Milky Way. Their high-speed encounters shock the galaxy, creating arcs, as seen in this newly released image from NASA’s Spitzer Space Telescope.

In this case, the speedster star is known as Kappa Cassiopeiae. It is a massive, hot supergiant moving at around 1,100 kilometers per second relative to its neighbors. But what really makes the star stand out in this image is the surrounding, streaky red glow of material in its path. Such structures are called bow shocks, and they can often be seen in front of the fastest, most massive stars in the galaxy.

Bow shocks form where the magnetic fields and wind of particles flowing off a star collide with the diffuse, and usually invisible, gas and dust that fill the space between stars. How these shocks light up tells astronomers about the conditions around the star and in space. Slow-moving stars like our sun have bow shocks that are nearly invisible at all wavelengths of light, but fast stars like Kappa Cassiopeiae create shocks that can be seen by Spitzer’s infrared detectors.

Incredibly, this shock is created about 4 light-years ahead of Kappa Cassiopeiae, showing what a sizable impact this star has on its surroundings.