N103B (also known as SNR 0509–68.7) is a supernova remnant located in the Large Magellanic Cloud.^[1] It is relatively close to Earth, allowing astronomers to observe and study the remnant. It lies a short distance from NGC 1850. The exact type of supernova that produced N103B is under speculation,^[2] but has been widely accepted to be a Type Ia supernova.^[3] It is within the boundaries of the constellation Mensa.

The orange-red filaments visible in the image show the shock fronts of the initial supernova explosion.^[3] These filaments have allowed astronomers to calculate the original barycenter of the explosion. The filaments also show that the explosion is no longer expanding as a sphere, but is elliptical in shape. Astronomers assume that part of material ejected by the explosion interacting with an extremely dense cloud of interstellar material,^[4] which slowed its speed. N103B is theorized to be interacting with dense circumstellar matter.

A double-ring structure is visible within N103B, implying that it expands into an hourglass-shaped cavity and forms bipolar bubbles.

Using the Chandra Telescope, astronomers observed N103B to figure out the initial supernova type.^[5] Due to the type of material and the amount of specific materials within N103B, astronomers were able to support the widely accepted belief that it was formed from a Type Ia supernova.^[6]

• List of supernova remnants
• List of supernovae

• N103B at NED