C/2018 F3 Johnson
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Comet C/2018 C2 was discovered on 20 March 2018, about seven months after its perihelion passage and was was last seen on less than a three weeks later on 6 April.

Therefore, the solution given here is based on post-perihelion data, spans over 0.047 yr in a very narrow range of heliocentric distances from 3.38 au to 3.51 au, and orbital parameters are uncertain (orbit of 3b quality class).
solution description
number of observations 51
data interval 2018 03 20 – 2018 04 06
data type observed only after perihelion (POST)
data arc selection entire data set (STD)
range of heliocentric distances 3.38 au – 3.51au
detectability of NG effects in the comet's motion NG effects not determinable
type of model of motion GR - gravitational orbit
data weighting NO
number of residuals 88
RMS [arcseconds] 0.42
orbit quality class 3b
previous orbit statistics, both Galactic and stellar perturbations were taken into account
no. of returning VCs in the swarm 2342
no. of escaping VCs in the swarm 2659
no. of hyperbolas among escaping VCs in the swarm 2639 *
previous reciprocal semi-major axis [10-6 au-1] -3,179.54 – -135.60 – 2,791.32
previous perihelion distance [au] 2.475 – 2.479 – 2.482 R
previous aphelion distance [103 au] 0.53 – 1.3 – 7.5
time interval to previous perihelion [Myr] 0.004 – 0.017 – 0.2 R
percentage of VCs with qprev < 1099
percentage of VCs with qprev > 201
previous orbit statistics, here only the Galactic tide has been included
no. of returning VCs in the swarm 2343
no. of escaping VCs in the swarm 2658
no. of hyperbolas among escaping VCs in the swarm 2639 *
previous reciprocal semi-major axis [10-6 au-1] -3,179.59 – -135.60 – 2,791.32
previous perihelion distance [au] 2.4745 – 2.4786 – 2.4807 R
previous aphelion distance [103 au] 0.53 – 1.3 – 7.5
time interval to previous perihelion [Myr] 0.004 – 0.017 – 0.2 R
percentage of VCs with qprev < 10100