Follow-up Imaging Observations of the fragmented Comet C/2025 K1
ATel #17510; M. Mugrauer (AIU Jena), M. Belger (AIU Jena), Z. Jamil (AIU Jena), S. Aruna Ravi (AIU Jena), B. Dincel (AIU Jena), K.-U. Michel (AIU Jena)
on 30 Nov 2025; 17:39 UT
Credential Certification: Markus Mugrauer (markus@astro.uni-jena.de)
On 18 November 2025 (03:30 UT) we took follow-up images of the fragmented comet C/2025 K1 (ATel #17487) using the Schmidt-Teleskop-Kamera (STK), which is operated in the Schmidt focus of the 90 cm telescope at the University Observatory Jena. A total of 14 images were taken in the R-band with a detector integration time (DIT) of 60 s each. During the observation the comet was at a distance of 0.45 au from Earth and 1.07 au from the Sun. We detected three fragments with an angular separation of 7.4 ± 0.2 arcsec (2422 ± 65 km of projected separation) between the eastern and central fragment and 9.4 ± 0.4 arcsec (3066 ± 128 km of projected separation) between the central and western fragment. The central fragment is the brightest of the three fragments, that are visible in the STK images. The magnitude difference between the eastern and central fragment is 0.9 ± 0.1 mag, and 0.4 ± 0.2 mag between the western and central fragment, respectively. We observed C/2025 K1 again on 21 November 2025 (02:50 UT) when the comet was at a distance of 0.42 au from Earth and 1.13 au from the Sun. A total of six STK images were taken with DIT=30s in the R-band. The three fragments were detected again with an angular separation of 9.5 ± 0.1 arcsec (2881 ± 36 km of projected separation) between the eastern and central fragment and 10.4 ± 0.1 arcsec (3141 ± 40 km of projected separation) between the central and western fragment. The projected separation between the fragments increased by approximately 10% between the two observation epochs. Also the brightness of the fragments has significantly changed between both observation epochs. In the 2nd epoch STK images the eastern fragment is the brightest of the three detected fragments, while the central one is the faintest. The magnitude difference between the central and eastern fragment is 0.7 ± 0.1 mag, and 0.5 ± 0.1 mag between the western and eastern fragment, respectively.
Follow-up Imaging Observations of the fragmented Comet C/2025 K1 - Online Data
