Colliding White Dwarfs Produced Bizarre Slime-Green Zombie Star - ScienceAlert
While main sequence stars such as our Sun fuse nuclear material in their cores to keep themselves from collapsing under their own weight, white dwarfs use an effect known as quantum degeneracy. The quantum nature of electrons means that no two electrons can have the same quantum state.Subrahmanyan Chandrasekhar made a detailed calculation of this limit in 1930 and found that if a white dwarf has more mass than about 1.4 Suns, gravity will crush the star into a neutron star or black hole.It was suggested that the object could be an unstable merger of two white dwarfs.
This is consistent with the object having been created by a white dwarf merger.
It likely has a high rotation, which prevents the object from collapsing into a neutron star.