It is now around 45 days since the initial reports of fragmentation of
this comet appeared in various sources (including ATEL 17482) and we
have almost daily images of the comet taken by BAA observers and
included in the archive here:

https://britastro.org/cometobs/2025k1/thumbnails.html

The current situation is that only two fragments are visible in amateur
images. These are the (presumed) original nucleus, A, and fragment C,
which is currently dominant. This seems a stable situtaion now and the
comet is rapidly fading as it moves away from the Sun and the Earth.

The first fragment to become visible in amateur images was fragment B
around November 10. This fragment faded and became unmeasurable around
November 23. A second fragment (fragment C) became visible between A and
C around November 15. This has survived and it is currently the
brightest of the two remaining fragments. A fourth fragment, D, became
visible between A and C at the end  of November and it was, briefly the
brightest object but it faded and became unmeasureable around December 6.

I have used Findorb and astrometry from BAA observers (stations 970,
I79, I81, J95, R64, Y81, Z10, Z17, Z30 and Z31) to compute the orbits of
the two remaining fragments. For fragment A I have used all of the
available MPC astrometry prior to November 5 and all the BAA astrometry
from the point that it was clearly separated from fragment B. For
fragment C I have used all the BAA astrometry from November 15 to
December 19. The computed orbits with no constraints are:

Epoch 2025 Dec 19.0 TT = JDT 2461028.5

K1-A

q   0.33419217 +/- 8.69e-7          Peri.  271.02045 +/- 0.00013
z  -0.0007161847 +/- 1.6e-6         Node    97.55827 +/- 0.000053
e   1.0002393 +/- 5.36e-7           Incl.  147.86490 +/- 0.000038
2410 of 2441 observations 2025 Apr. 8-Dec. 19; mean residual 0".74

K1-C
n   0.00007123 +/- 1.61e-5          Peri.  270.85330 +/- 0.015
a 576.338220 +/- 66.8               Node    97.51113 +/- 0.0042
e   0.9994216 +/- 8.25e-5           Incl.  147.83491 +/- 0.0026
q 0.33330462 +/- 8.09e-5    Q 1152.34313 +/- 134
131 of 139 observations 2025 Nov. 15-Dec. 19; mean residual 0".54

Using these orbits we can estimate the physical separation of the two
fragments at the epoch (Dec 19.0). This corresponds to around 73,000 km.
The current difference in the magnitude of the heliocentric velocity
vectors is around 33 m/s. This is consistent with a separation velocity
of a few tens of m/s in mid November which is what you might expect for
a fairly violent separation process.

A draft of a figure that I am producing for a report in the next Journal
showin the comet's evolution from early November is here:

https://nickdjames.com/Comets/2025/2025K1/2025K1_frags_rev0.2.jpg

Nick.