CTB 1, also known as G116.9+00.1 and AJG 110,[1] nicknamed the Medulla Nebula,[2] is a supernova remnant located in the constellation Cassiopeia.

[3] CTB 1 is an oxygen-rich supernova remnant of mixed morphology, that is, in the radio band it is similar to a hollow shell while in X-rays its structure is compact and centralized.

The radio emission is brightest along the western edge, with a prominent gap existing along the northern and northeastern sectors.

[4] The X-ray emission from this supernova remnant – which has a thermal origin – comes from inside the shell, observed in the visible and radio spectrum.

Likewise, the direction and morphology of the plerion tail suggests a physical connection between PSR J0002+6216 and CTB 1.