This strange phenomenon is located about 1300 light years from Earth in the constellation of Puppis, which is also known as the Poop Deck or Stern. Cometary globule CG4 has nothing to do with comets, it’s actually a faint nebula, despite its bright and vivid colors as seen in this picture.
The head of CG4, which is the part visible on this image has a diameter of 1.5 light-years, while its tail is about eight light-years long.It's head part is only visible because it is illuminated by the light from nearby stars. The radiation emitted by these stars is gradually destroying the head of the globule and eroding away the tiny particles that scatter the starlight. However, the dusty cloud of CG4 still contains enough gas to make several Sun-sized stars and indeed, CG4 is actively forming new stars.
Astronomers hope to study more cometary globules, like CG4 to solve the mystery of why they have their distinct shapes.
article reference:- eso.org