C/2025 R2 (SWAN) (CK25R020)

Type: Periodic Perihelion date: 12 September 2025 Perihelion distance (q): 0.5 Aphelion distance (Q) : 152.6 Period (years): 669.7 Eccentricity (e): 0.99 Inclination (i): 4.5 JPL orbit diagram COBS lightcurve Atlas On 12 September 2025, Sam Deen reported on comets-ml that a friend of his had spotted an object in STEREO-A HI1 over the past few weeks and moving to a higher elongation. Vladimir Bezugly responded that he had reported an object in SWAN imagery visible since 4 September 4 and this would soon appear on the PCCP. He had asked Martin Masek to try imaging it and he had obtained ground based confirmation; other observations soon followed. It was at perihelion at 0.5 au on 12 September and will pass 0.27 au from the Earth on 21 October. The Earth MOID is 0.05 au and the Jupiter MOID is 0.04 au. The comet is intrinsically faint. Observations (VEMag = visual equivalent magnitude) Date 10x10 mag Error VEmag Coma ' 10-Oct-25 6.7 9.5 06-Dec-25 13.1 1.7