What is a characteristic of SS433 regarding its primary star?

SS433 is a binary star system that has garnered significant attention due to its unique characteristics. The primary star in this system is particularly noteworthy as it is believed to be either a black hole or a neutron star. This determination is based on the high-energy emissions observed from the system, specifically the relativistic jets that are ejected at high velocities. The existence of velocities nearing the speed of light suggests that the primary component is extremely dense, which is consistent with the properties of black holes or neutron stars.

The high mass accretion from the companion star onto the primary also contributes to the energetic output observed in SS433, reinforcing the conclusion that the primary is indeed a compact object such as a black hole or neutron star. In contrast, the other options describe characteristics that do not align with the established understanding of SS433's primary component. For instance, while it is luminous due to its energetic emissions, it does not fit the classification of a red dwarf star or a known supernova. Thus, the primary star's classification as a potential black hole or neutron star is a key characteristic that defines SS433's behavior and significance in astrophysics.