Description:
SNR G304.4−3.1 is a faint and relatively obscure supernova remnant located in the southern constellation Musca, in the rich stellar field surrounding the multiple star system Theta Muscae. It lies at an estimated distance of about 7,400 light-years from Earth.
This object is not one of the bright, well-defined remnants like the Crab Nebula. Instead, it is subtle and fragmented—more a ghostly network of filaments than a clearly bounded shell.
Although SNR G304.4−3.1 lies in the same region of the sky as Theta Muscae, it is not believed to be physically associated with that system.
This is an important distinction: the apparent proximity is a line-of-sight coincidence, common in the crowded plane of the Milky Way.