C/2025 R2 (SWAN)
Comet C/2025 R2 (SWAN) imaged from the Siding Spring Observatory on 13 September 2025 with a 0.5 m (20 in) telescope. | |
| Discovery | |
|---|---|
| Discovered by | SOHO–SWAN Vladimir Bezugly |
| Discovery date | 11 September 2025 |
| Designations | |
| SWAN25B, CK25R020 | |
| Orbital characteristics | |
| Epoch | 11 November 2025 (JD 2460990.5) |
| Observation arc | 197 days 168 days (without STEREO-A) |
| Earliest precovery date | 13 August 2025 |
| Number of observations | 2225 |
| Aphelion | 177 AU (inbound) 167 AU (outbound) |
| Perihelion | 0.5041 AU |
| Semi-major axis | 89 AU (inbound) 84 AU (outbound) |
| Eccentricity | 0.9943 (inbound) 0.9940 (outbound) |
| Orbital period | ≈840 years (inbound) ≈770 years (outbound) 810 years (near perihelion) |
| Inclination | 4.4730° |
| 335.33° | |
| Argument of periapsis | 308.36° |
| Mean anomaly | 0.072 |
| Last perihelion | 12 September 2025 |
| TJupiter | 0.936 |
| Earth MOID | 0.048 AU |
| Jupiter MOID | 0.042 AU |
| Physical characteristics | |
Mean radius | 0.3–1.0 km (0.19–0.62 mi) |
| Comet total magnitude (M1) | 13.9±1 |
| 6.0 (2025-09-26) | |
C/2025 R2 (SWAN), formerly known as SWAN25B, is a long-period comet discovered on 11 September 2025 by Vladimir Bezugly through SWAN imagery. The comet peaked around apparent magnitude +6 in late September 2025.