C/2025 R2 (SWAN)
Long-period comet discovered via SOHO's SWAN instrument in September 2025.
Last updated
C/2025 R2 (SWAN), formerly known as SWAN25B, is a long-period comet discovered on 11 September 2025 by amateur astronomer Vladimir Bezugly through SWAN imagery on the Solar and Heliospheric Observatory (SOHO). It peaked around apparent magnitude +6 in late September 2025 and is notable as the 20th comet discovered through SOHO's SWAN instrument.
Background
The comet was first spotted in SWAN images on 11 September 2025 by Vladimir Bezugly, with an estimated magnitude of 7.4 and a tail about 2 degrees long. It was located in the constellation Virgo and better seen from the southern hemisphere. The comet was not discovered earlier due to the Holetschek effect, being less than 30 degrees from the Sun between August 7 and September 13. It rapidly brightened from magnitude 11 to 8 between August and September, reaching magnitude 6.2 on 16 September.
An outburst later in September brought it to magnitude 5.9. On 2 October it passed near Zubenelgenubi, and on 17 October it passed directly over Messier 16. On 2 November 2025, a possible fragmentation event was observed from the Two-meter Twin Telescope at Teide Observatory, with reports of the nucleus splitting or releasing a substantial fragment, likely occurring around mid-October. NASA announced in December 2025 that the PUNCH spacecraft observed the comet between 25 August and 2 October 2025.
More in Named Comets
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: C/2025 R2 (SWAN) (CC BY-SA 4.0).
- Word definitions: the , each quoted from its Wikipedia article.
Spotted an error? Know more?
Reader corrections go straight into our review queue. Suggest an edit · How this site is sourced