Following the circular No. 4594, here is an observation of 06478 GAULT, which presents a cometary activity.

=> T400RC Remote, SpaceObs., Chili :

Cometary appearance activity 06478, without filter, 50x60s, sampling of 1.12"/pixel,
Coma : 15", Tail : +/-4' long, structure direction the tail of PA : +/-300°,
m2 : 17.4 (+/-0.3), aperture radius for measures : 6.7"
dRA : -0.3' and dDe : +0.1'

Astrometry :
NET UCAC-4
06478 KC2019 01 08.32474 10 48 19.39 -12 35 37.1 17.3 R W96
06478 KC2019 01 08.34505 10 48 19.48 -12 35 39.5 17.4 R W96
06478 KC2019 01 08.37097 10 48 19.57 -12 35 42.6 17.5 R W96

Hello all:
(1) I do not understand why some people are suggesting that 6478
is the result of an impact. It does not look like. The object
resembles more 133P/Elst-Pizarro in its morphology.

(2) 6478 is now 362 days before perihelion, the point with largest
insolation in the orbit and thus temperature. So it is surprising
that it is so active so far from the Sun. The reason might be that
the North pole is now pointing to the Sun and thus the Sun
never sets. However,

(3) the object exhibits a very straight dust tail and no gas tail.
This might be understood if the object is very old and has
run almost out of gas. The little gas that is left raises very
fine dust that is carried away by the solar wind in a straight
trayectory.

In other words, might be we are seeing a very old object
brother (or cousing) of 133P.

With the very helpful observation forwarding from numerous different observers over the last week or so, I can now confidently say that 6478 Gault has a noticeably different orbit post-impact than pre-impact:

Perihelion 2020 Jan 2..867871 +/- 4.51e-5 TT = 20:49:44 (JD 2458851.367871)
Epoch 2019 Jan 14.0 TT = JDT 2458497.5 Earth MOID: 0.9902 Find_Orb
M 260.35159 +/- 0.000012
n 0.28159777 +/- 1.58e-9 Peri. 83.25358 +/- 0.000018
a 2.30524223 +/- 8.64e-9 Node 183.55831 +/- 0.000013
e 0.1935338 +/- 5.1e-8 Incl. 22.81079 +/- 0.0000053
P 3.50 H 14.7 G 0.15 U -0.6
q 1.85909994 +/- 1.18e-7 Q 2.75138452 +/- 1.17e-7
1055 of 1085 observations 2000 Dec. 22-2018 Feb. 9; mean residual 0".51

Perihelion 2020 Jan 2.751937 +/- 0.116 TT = 18:02:47 (JD 2458851.251937)
Epoch 2019 Jan 14.0 TT = JDT 2458497.5 Earth MOID: 0.9892 Find_Orb
M 260.34641 +/- 0.012
n 0.28170469 +/- 9.39e-5 Peri. 83.29274 +/- 0.033
a 2.30465891 +/- 0.000512 Node 183.54996 +/- 0.007
e 0.1938272 +/- 0.000272 Incl. 22.81288 +/- 0.0018
P 3.50 H 13.2&nb sp; G 0.15 U 6.5
q 1.85795312 +/- 0.00103 Q 2.75136471 +/- 0.000148
24 of 30 observations 2018 Oct. 27-2019 Jan. 14; mean residual 0".20

a: -0.000583 +/- 0..000512 AU
e: +0.000293 +/- 0.000272
i: +0.00201 +/- 0.00180
node: -0.0084 +/- 0.0070
peri: +0..039 +/- 0.033
long_peri: +0.031 +/- 0.040
q: -0.00115 +/- 0.00103 AU
Q: -0.0000198 +/- 0.000148 AU (still remains very insignificant)

So whatever impacted this asteroid must have had a lower perihelion, a relatively similar aphelion (the impact occurred near aphelion anyway so it wouldn't have changed much regardless), and even possibly a higher inclination. I' m not sure how it would have a larger inclination than the already highly inclined 6478 Gault, but I guess I can't argue with the data.