3C 309.1 has a triple radio structure. It has a radio core found self-absorbed with an extended position angle of 162° ± 2°. On both sides of the core, there are two relatively extended outer radio lobes having a defined positional angle of 90°.[6]
In sub-arcsecond resolutions, the structure is made up of several components. Three of them are aligned east–west while the others are located along the path of extended emission in a southern direction, clearly detected by two X-ray images. In two of the brightest components, there is polarized emission.[7] However, when viewed at a 5 GHz milliarcsecond (mas) resolution, a bright core is found instead straddled by two other weaker components with a separation of 8.7 kiloparsecs.[8] Sub-milliarcsecond imaging shows the core to be compact with a more extended component located 20 mas to the south.[9]
The jet of 3C 309.1 is one-sided. It is found to be flaring away from the nucleus with a sharp change in brightness, likely caused through various Kelvin-Helmholtz instabilities in confined fluid flow and pressure being exerted in confined medium.[10] In Very Long Baseline Interferometry radio imaging, the jet is shown to extend from the core southwards with a distance of 260 parsecs (60 mas). At eastwards, it bends at 90° before fading rapidly.[8] Furthermore, the jet is extremely polarized.[11][12]
The host galaxy of 3C 309.1 is a flat elliptical galaxy according to Hubble Space Telescope imaging. It has a major axis orientated along the position angle of 130°.[13] Extensive emission-line gas is also seen surrounding the object at high pressure, with a massive cooling rate exceeding 1000 Mʘ yr−1 implying its host galaxy might have been formed within a Hubble time.[14]